Sir John Gorst: Right-wing libertarian MP best remembered for his role in the 1970s Grunwick dispute

John Gorst was a very considerable publicist, not only for the causes in which he was interested, but for his own part in promoting them.

The knighthood he received in 1994 would seem scant reward, but he was never particularly ambitious. He knew that he would quickly become bored with being a junior minister and that he was too much his own man – some would say too maverick – to hope for anything more.

Perhaps the most striking episode in his career, certainly the one which had most impact on the national scene, was the Grunwick dispute. The owner of the Grunwick photo processing firm, George Ward, had sacked part of his work force for striking and joining the trade union APEX. In the long dispute which followed, Gorst was at his side at every press conference and every meeting, masterminding tactics and continually reciting a powerful litany based on the importance of freedom, the right to work and the dangers of corporatism. It was attractive not merely to the right but to a great many in the centre who were beginning to think trade union power excessive.

The TUC encouraged sympathetic action, but when the local branch of the postal workers refused to deliver the firm's mail Gorst organised what he called his "pony express", volunteers who delivered the mail to post offices outside the area. The National Association for Freedom sued the Union and forced a compromise. When the picketing turned violent and the strikers were joined by students, by the Socialist Workers Party and Arthur Scargill's miners from Yorkshire, South Wales and Kent, the TUC and the Labour Government were embarrassed and the Conservative shadow cabinet split.

The Government bought off the pickets by commissioning the Scarman enquiry, but Ward refused to accept its findings; he turned to the Courts, obtaining a ruling in his favour late in 1977. It was something of a pyrrhic victory since it cost the Freedom Association almost £80,000, but in retrospect he could argue that it was an important link in the chain of events that led to public acceptance of Mrs Thatcher's drive to reform trade union law.

John Michael Gorst was the great-grandson of John Eldon Gorst, who organised Disraeli's election victory in 1874 and later held a succession of offices. Gorst never knew him, but he seems to have inherited his independence of mind. On the side of his father, Charles, he was three parts Irish, while his mother, Tatiana Kolotinsky, was a daughter of a Colonel in the Tsar's Imperial Guard who had escaped from Russia at the time of the Revolution.

Gorst was educated at Branksome-Hilders school in Haslemere, at Ardingly, and at Corpus Christi, Cambridge, where he read history and modern languages. He taught from 1951-53 but decided that he needed to make more money. After working briefly at a holiday camp in Bognor Regis and managing a Shakespearian touring company in the Lake District, he got a job with Pye's advertising department and his career flourished. At first their press officer, he became their first public relations manager, providing journalists with free TV sets and entertaining them at lavish lunches.

In 1964 he left to set up his own PR firm, John Gorst and Associates, and he perfected the use of trade associations and pressure groups like the Telephone Users Association, the Local Radio Association, and the Contract Cleaning Association. Among his earliest clients were British Lion Films, the Federation of British Film makers and the Film Production Association of Great Britain. He retained links with the media throughout his career and in the 1980s argued strongly in Parliament for the BBC and ITV to pay a levy for every film they screened.

Retained by Guy's Hospital in 1968, he volunteered as spokesman for the National Heart Foundation when heart transplants began and handled the public relations for the second and third cases, Gordon Ford and Charles Hendrick. He was known to clash violently with his clients on occasion, and many dispensed with his services after a few months; the break was sometimes at his instigation. He acted as a consultant to the British Airline Pilots' Association and argued their case with great skill in a number of disputes with BOAC, but he quit in 1968 when the union's leaders refused to let him lobby Conservative MPs.

His active political career was the result of a drunken boast at a cocktail party, and he was initially unsuccessful at getting on to the Conservative candidates' list. Turned down in 1960, he re-applied, fought Chester-le- Street in 1964 and two years later took on the Liberal, Peter Bessell, at Bodmin. He became associated with the Society for Individual Freedom and used the 750th anniversary of Magna Carta to further its work. He also founded the Enterprise Association to campaign against further nationalisation. Adopted to succeed Sir Ian Orr-Ewing at Hendon North, he took the seat in 1970 by 3,179 votes and held it until 1997.

From the first he could be a thorn in the party's flesh. He was one of three MPs to oppose Selwyn Lloyd's election as Speaker. He opposed the timing of the introduction of VAT as lunatic, given the rapid rise in prices, and when the Government brought forward its plans for commercial radio was able to derail two of its proposals, that local newspapers should have an automatic stake in local radio stations and that London's news stations should supply the news nationwide. He became a director of Standard Broadcasting and was an important source of advice on setting up commercial radio stations.

In 1974 he launched the Middle Class Association, to defend a "persecuted, vilified and sneered-at" minority, managers and the self-employed. As he admitted, the move misfired, but Gorst was quick to regroup, becoming a staunch supporter of Thatcher's leadership campaign, merging the Middle Class Association with the newly-founded National Association for Freedom and making himself something of a national figure over Grunwick. That made him one of the leading protagonists of trade union reform; and after the 1979 election he did not hesitate to take on the Employment Secretary, Jim Prior, criticising his reform of picketing laws as "mild and minimal".

Early in 1980 he went further, accusing Prior of cowardice, and followed up his amendment to outlaw the closed shop with amendments to make union ballots compulsory and to use union funds to compensate employers affected by secondary action. "We were elected to get trade union reform through on Conservative votes", he told Prior, "not to resist it on Labour votes." By July 1980 he was accusing him of having tricked the party over union reform and described him as a "dangerous liability". He found Prior's successor, Norman Tebbit, much more to his liking, but could never persuade him to outlaw strikes in essential services.

In general he stood to the right of his party but remained a libertarian, voting with the opposition to put penalties on illegal phone tapping into the British Telecom bill. Even more striking, he voted with them on their demand that the Coal Board review the case of every miner sacked during the year-long strike. He was also critical when the Government refused to allow unions at GCHQ, and was one of four Tories to vote against the third reading of the 1989 Official Secrets Act; he had backed a cross-party effort to provide whistle blowers with a public interest defence..

His judgement could be awry. He made an ill-judged claim to speak Swahili during the 1974 election campaign and he insisted on taking up the case of a former Guards officer, Simon Hayward, whom the Swedish Government had jailed for drug smuggling in 1987. His criticisms of the Swedish judicial system were regarded as ill-founded, but he could not be faulted for his loyalty to Hayward. When he was released half-way through his five-year sentence, Gorst criticised the BBC for not carrying an interview with him.

In 1994 he was drawn into the "cash for questions" scandal. While he made it clear to the undercover reporters that he would ask the suggested questions without payment, he also indicated that he would not be averse to some future arrangement. When this was reported, he attacked the journalist for "bribery and bugging".

However, he won back some credit with his call for Rupert Murdoch to be barred from ownership of Channel 5 and his last years in the Commons were given to a campaign to save the A&E department at the Edgware Hospital. When his lobbying did not look to be succeeding, he and his fellow campaigner Hugh Dykes made it clear they would resign the Conservative whip unless concessions were made. The concessions, however, were not enough to save him from defeat in the 1997 election. The constituency boundaries had been redrawn and despite the regard in which he was held, even by political opponents, he was heavily defeated.

Gorst took the chair of Chadwick Associates Ltd in 1997 and moved to Sherborne. He is survived by his wife, Noel Harington Walker (the ballerina, Noel Rossana). They had five sons.

John Michael Gorst, politician and public relations consultant: born 28 June 1928; MP, Hendon North 1970–97; Kt 1994; married 1954 Noël Harington Walker (five sons); died 31 July 2010.