Why Boris Johnson and the Tories should be worried about the Old Bexley and Sidcup by-election result

The Conservatives should be concerned about the Old Bexley and Sidcup by-election result. On the face of it, their reduced majority on a lower turnout was respectable enough for a government afflicted by mid-term blues. However, the Tories should fret about the informal cooperation between two opposition parties which saw a 10 per cent swing to Labour and the Liberal Democrats fall into fifth place.

Their below-the-radar pact has already deprived the Tories of two by-election victories in Chesham and Amersham, and Batley and Spen. The Lib Dems soft-pedalled in Old Bexley and Labour won’t pull out all the stops in Shropshire North on 16 December in a tacit acceptance that the Lib Dems are the main challenger; the Tories are increasingly nervous about the contest caused by Owen Paterson’s resignation. Defeat would cap a terrible patch for Boris Johnson and fuel the debate among Tory MPs about whether he has lost his stardust.

Keir Starmer and Ed Davey have ruled out a formal electoral pact in which their parties stood down in some seats, thinking it would smack of weakness, and would not move their voters from one column to another. But their cessation of hostilities – now the wounds of the Lib-Con coalition are healing – poses a real threat to the Tories. The Corbynistas still hate the Lib Dems but Jeremy Corbyn has been marginalised, while the pro-European centrists in Team Starmer are willing to make common cause with the Lib Dems for the greater good of ending Tory hegemony.

Slowly, the two opposition parties are defining themselves. Starmer did so in this week’s wide-ranging shadow cabinet reshuffle and now has the team he wants, with hungry Tory attack dogs and good media performers in key posts. One ally told me the shake-up marked “the end of [his deputy] Angela Rayner’s attempt to be Labour’s co-leader”.

Starmer’s new-found confidence is reflected in his more aggressive attacks on the Tories – not before time. A few months ago, I doubt the instinctively cautious Labour leader would have raised at Prime Minister’s Questions the reports about two Downing Street parties before last Christmas. But doing so this week ensured broadcasters ran with the latest damaging “one rule for us” story. Similarly, I doubt Labour would have previously used the c-word – corruption – about allegations of “Tory sleaze” as it now does.

However, the new shadow cabinet will not become a government-in-waiting until Labour unveils a few keynote policies Johnson can’t steal, to show floating voters what difference the party would make.

Similarly, an attempt to spell out what the Lib Dems stand for has been launched by five prominent party members. Chris Bowers, co-author of The New Liberal Manifesto, said the party has been defined in relation to the Tories and Labour rather than in its own terms. The manifesto admits candidly the Lib Dems “have to stand for something” or will risk “being seen as ‘yellow Tories’ to disappointed Labour supporters, and ‘closet socialists’ to cynical Conservatives.”

The group also hopes a better understanding of where opposition parties stand will help them work together. Message to Labour: the Lib Dems are a progressive party and you will need us to help get the Tories out. The manifesto argues that liberalism’s core tenets of liberty, equality, community, environment, democracy and internationalism mean its time has come again as the UK moves away from “the old left-right divide”. It says: “Liberalism offers a perfect alternative to the Conservatives for the next British general election, whether presented solely by the Liberal Democrats or as a framework for cross-party cooperation among socialists, social democrats, social liberals, greens, liberal conservatives and others. A new incarnation of liberalism could be exactly what those often labelled ‘progressives’ are looking for.”

Compass, which campaigns for a progressive alliance, says the lesson from Old Bexley is that progressive parties must work together in every seat where only one can win. Neal Lawson, its director, said Labour and the Lib Dems should go further than “under-the-radar targeting”. He recalled that there was more public cooperation between the two parties before the 1997 general election when the challenge was less daunting, saying: “’Ninety-seven minus isn’t good enough when we need ’97 plus.”

Indeed, Labour and the Lib Dems will need to repeat their by-election cooperation at the general election. Johnson would accuse them of trying to create a “coalition of losers” but the Tories would be the losers once they were deprived of their overall majority, because no other party is likely to prop them up. Achieving that would require a swing of about 4 per cent to Labour rather than the 10 per cent needed for a Labour overall majority.

To have any chance of ousting the Tories, Labour and the Lib Dems need to concentrate their fire on Johnson’s party and not let small differences divide or divert them. There is no guarantee such cooperation will deliver a non-Tory government but there is no road to power at the next election without it.