Conservatives may be reduced to their lowest ever number of councillors in London at the local elections on May 3 but could hold onto their flagship councils of Wandsworth and Westminster, a leading elections pundit has said.

“Labour had success in London in the 2017 general election and I would expect this to continue in 2018,” Tory former MP Robert Hayward (now Lord Hayward) told a media briefing in the capital ahead of the polls at 150 councils in England including all 32 London boroughs.

He indicated the number of Conservative councillors could fall below the previous low of 519 recorded at the 1994 London borough elections. They won 612 seats at the previous polls in the cycle in 2014.

“I would be surprised if the Tories do not have an all-time low in the number of their councillors in London this May,” he said.

However, in contrast to some other forecasts of a Tory debacle, he expected the party could hold onto Wandsworth, which has been controlled by Conservatives since 1978, and Westminster, controlled by Tories since 1964.

Conservatives could also do relatively better outside the capital. The analyst told the briefing hosted by policy research consultancy ComRes: “You will see a marked difference between the polls in London and the rest of England.”

Figures from political researchers YouGov and Professor Tony Travers of the London School of Economics showed Labour’s vote share was much bigger and that of the Tories much smaller in London than their overall general election vote shares in Great Britain but that position was reversed outside of London.

“I would expect Conservatives to lose seats overall but not to such an extent as to endanger Theresa May’s premiership,” Mr Hayward said.

“Labour should be doing better outside London but I don’t know whether Labour will take Trafford.”

Prof Travers told the briefing: “Conservatives have been doing well in local government for a party that has been in power for eight years.”