Labour have held two seats in the parliamentary by-elections as parties await the result of the hotly-contested marginal seat of Corby.
Stephen Doughty claimed Cardiff South and Penarth, winning 9,193 votes, while Lucy Powell won in Manchester Central with 11,507 votes.
Neither result was unexpected but encouragingly for Labour there were swings towards the party in both constituencies. In Manchester Central, the swing away from the Liberal Democrats was 16.77%.
In Manchester, the turnout of 18.16% was the lowest in a parliamentary by-election since the Second World War. Tory candidate Matthew Sephton he lost his deposit as he only managed 754 votes, less than 5% of the total turnout.
Voter turnout in Cardiff was higher at 25.65%, with a swing from the Conservatives to Labour of 8.41%.
Prime Minister David Cameron and Labour leader Ed Miliband will now wait anxiously for the result in Corby in Northamptonshire. Turnout there has been confirmed at just under 45%.
The by-election was triggered in August when chick-lit author Louise Mensch gave up her seat to spend more time with her family in New York.
From 1997 to 2010 Corby was held by Labour's Phil Hope. But Mrs Mensch managed to take it off him with a slim majority of just under 2,000.
Labour sources said they were "cautiously optimistic" they had won the seat back, with turnout expected to be as high as 40%.
Meanwhile, Mrs Mensch took to Twitter to tell followers that she took responsibility if the Tory candidate Christine Emmett failed to hold on to Corby.
She tweeted: "Election result will not be a verdict on either Christine, or the Conservatives, but only on the decision I took to step down mid-term."
Mrs Mensch added: "Though I had to resign to unite our family, there was large & entirely understandable local anger. I wish I had been able to see out my term."
The Tories' majority in Corby at the last election was 1,951 but since then Labour has established a solid lead in opinion polls.
Tory efforts were further hampered by controversy on Tuesday night when it emerged their campaign manager Chris Heaton-Harris had encouraged a rival candidate.
Manchester Central was vacated by Tony Lloyd so he could stand in the Police and Crime Commissioner (PCC) elections.
Cardiff South and Penarth, where Labour won by just over 4,700 votes two-and-a-half years ago, was prompted by the resignation of another PCC candidate, Alun Michael, who had held the seat for 25 years.