Fisheries minister who doesn't know his fish

The fisheries minister, Richard Benyon, has spent much of his time in the job locked in complex negotiations in Brussels over EU quotas – so much time, in fact, that he apparently has not been able to learn what the animals look like.

In a mischievous impromptu test by a Channel 4 show to be screened tonight, the man in charge of Britain's fishing fleet struggled to name 12 species such as haddock and plaice.

The minister managed two on his own: cod and monkfish and, with the help of the presenter, managed a third: pollock. Among the fish he could not spot were turbot, whiting and halibut.

Mr Benyon had acquitted himself well in an earlier interview with the chef Hugh Fearnley-Whittingstall for the programme Hugh's Big Fish Fight, agreeing that it was madness to force trawlers to throw back half the fish caught. "This has to stop," he said.

Unbeknownst to him, Fearnley-Whittingstall had lined up a "little bit of mischief".

Before the minister's arrival, the chef told the camera: "I really want to find out how well he knows his fish. He was shadow Fisheries minister for a long time and he is by all accounts quite passionate about this. But does he know haddock from whiting?" At the conclusion of the interview, Mr Benyon agreed he was "a passionate fish-eater", then looked uncomfortable as he was asked to identify the fish. "Oh God, this is so cruel. I'm a landlubber," said the MP for Newbury in Berkshire. "I come from as far away from the sea as you possibly can."

He joins a long list of MPs from all political parties who have demonstrated ignorance about things they should really know.

Er, i'll get back to you: politicians out of their depth

Alan Johnson

Mr Benyon's exposure comes only two days after the shadow Chancellor, Alan Johnson, was unable to answer a question about taxation on television. On becoming shadow Chancellor last year, Mr Johnson – whose job is to monitor £697bn of government spending – joked he would have to read an economics primer. Accused of being an economic "novice" by Sky's Dermot Murnaghan on Sunday, he was challenged to state the level of employer's national insurance contributions. The shadow Chancellor tried to dodge the question before saying he would increase it by 1 per cent, to 21 per cent. The presenter interrupted: "Sorry, national insurance, secondary class one-rate for employers, stands at the moment at ...?" There was an awkward pause, before Mr Murnaghan explained the figure was 12.8 per cent.

David Lammy

Mr Lammy scored 13 points on Celebrity Mastermind in 2008, coming last, while Higher Education Minister. He passed on the name given to the highest gallery of seats in a theatre (the Gods) and the American military award given to wounded soldiers (the Purple Heart). Asked which king ascended the throne aged nine on the death of his father Henry VIII in 1547, he replied: "Henry VII", then appeared to reproach himself. He correctly identified William Hague as the former Conservative leader who once boasted he used to drink 14 pints of beers a day while working as a delivery driver in his youth.

Luciana Berger

Luciana Berger displayed some weak spots in her local knowledge as she battled to become Labour MP for Liverpool Wavertree. After the city's Labour stalwart Peter Kilfoyle publicly criticised her knowledge, the Liverpool Echo gave her a short test last year, in which she failed to identify Bill Shankly, Liverpool football club's most famous manager.

She got two of the four questions right: "Who gave their name to Liverpool's airport?" (Answer: John Lennon) and, "How many Mersey tunnels are there?" (Answer: at least two). But she was stumped by the Shankly question and, "Which Liverpool group that sang 'Ferry 'Cross the Mersey'?" (Answer: "I've no idea"). On hearing who Bill Shankly was, she said: "You can't ask a girl a football question."

Richard Caborn

Labour's new Sports Minister fell at the first hurdle in a Radio 5 Sunday Service quiz on sports knowledge in 2001. This is how his exchange with Clare Balding went:

Balding: "Can you name the four players involved in today's semi-finals of the Stella Artois?"

Caborn: "Henman. I can't, no." (Correct answer: Henman, Ferreira, Sampras, Hewitt.)

Balding: "Can you name three jockeys who will be riding at Royal Ascot this week?"

Caborn: "No. I know nothing about horse racing at all." (Correct answer: Names could have included Frankie Dettori, Pat Eddery and Michael and Richard Hills.)

Balding: "Who is the current England cricket coach?"

Caborn: "The Aussie?" (Correct answer: Duncan Fletcher, from Zimbabwe.)

Balding: "Can you name three European golfers playing in the US Open?"

Caborn: "Montgomerie ... Europeans? I haven't been watching the golf at all." (Correct answer: a lot of Europeans playing, including Montgomerie, Sergio Garcia, Nick Faldo, Padraig Harrington.)

Balding: "Who's captain of the Lions?"

Caborn: "Don't know that one either – I'm terrible this morning." (Correct answer: Martin Johnson.)

David Cameron

The Prime Minister appeared to show a deep ignorance of Britain's finest hour. On the second day of his first official trip to meet the US President Barack Obama in July, Mr Cameron said: "I think it is important in life to speak as it is and the fact is that we are a very effective partner of the US but we are the junior partner. We were the junior partner in 1940 when we were fighting the Nazis."

In fact, Britain fought Hitler for two years before the Japanese attack on the American naval base at Pearl Harbour in Hawaii on December 7 1941 prompted the US to join the war. David Miliband, then shadow Foreign Secretary, sought to exploit the gaffe, protesting: "Millions of Britons stood up and gave their lives to defeat fascism. We were not a junior partner. We stood alone against the Nazis."

During a phone-in a retired telephonist Kathy Finn, whose step-father was a mine sweeper in the Navy, said: "It seems as if he [Cameron] was trying to appease America and flatter Obama because of BP. He didn't seem to know his recent history either. I voted for him but it makes me wonder if I was right to do so." Mr Cameron apologised for the error.