Labour's London elections campaign has received a much-needed council by-election boost in a key marginal assembly constituency.
The result, in a rare Wednesday contest, at East Finchley, Barnet Borough, showed a net swing of more than 16% to the party compared with the 2010 main polls on the same day as the General Election.
If repeated on May 3 this would be more than enough for it to capture Barnet and Camden, Tories' most marginal London Assembly constituency.
This is a tonic for Labour days after a poll put its mayoral candidate Ken Livingstone six points behind Conservative contender Boris Johnson.
In two London council by-elections last month there was also a big swing to Labour in Tories' flagship Wandsworth Borough and Liberal Democrats held a marginal Brent seat, aided by a squeeze on Conservatives' vote.
There are two more tests in the capital next week.
Tower Hamlets mayor Lutfur Rahman is backing an independent in his former Spitalfields and Banglatown ward against the Labour nominee, echoing an earlier bitter row which also involved Mr Livingstone.
Despite a decision by the party's National Executive Committee to block Mr Rahman from running under its banner in the 2010 poll for borough mayor, Mr Livingstone campaigned with him when he stood as an independent - and went on to win.
In that election Mr Rahman was backed by the Respect party of George Galloway, now Bradford West's MP, which won another of Spitalfields and Banglatown's seats when it was vacated by the new mayor.
Labour also seeks to defend a seat at Goresbrook, Barking and Dagenham Borough where the BNP came second in the last main polls in 2010 and in a by-election two months later.
:: Voting is under way today in two by-elections, at Darlington Borough in the North East and Newark and Sherwood, Nottinghamshire.
Barnet London Borough - East Finchley: Lab 2,117, C 543, Lib Dem 461. (May 2010 - Three seats Lab 3,315, 2,931, 2,868, C 1,994, 1,855, Lib Dem 1,735, C 1,723, Lib Dem 1,397, 1,237, Green 652, 588, 477). Lab hold. Swing 16.6% C to Lab.