Labour and main challenger the Scottish National Party both said there had been encouraging levels of support – but held on for a late flurry at polling stations for the 62,051 electorate by late afternoon.

SNP candidate John Mason was one of the first to cast a vote.

The serving Glasgow councillor echoed his party leader's earlier warning shot to Prime Minister Gordon Brown, saying: "If we win this seat, it's an earthquake."

One SNP activist said the support base was "highly motivated".

Labour's Margaret Curran, a former Holyrood minister who represents part of the area as an MSP, is trying to hold on to the seat which enjoyed a 13,507 majority at the last election.

She campaigned up to the wire, including a blitz of the checkouts at an Asda supermarket in the Parkhead area.

Ms Curran said: "As I promised at the beginning, I am working right up to 10pm, taking nothing for granted and working for every vote.

"I think Labour has had a very positive message for the voters and I have had a very positive response to the message."

Labour sent out about 400 activists to bolster support and said early indications pointed to a strong turnout.

Candidates for the other main parties were Liberal Democrat Ian Robertson, who is a local schoolteacher, and Tory Davena Rankin, a union activist.

The Conservatives said total voter numbers at the polls had been "patchy" but said they had stolen support from previous third place party the Lib Dems.

One Lib Dem activist said some 29 per cent of voters had been to polling stations by late afternoon.

The Glasgow East by-election was triggered by the resignation on health grounds of Labour MP David Marshall.

Losing the rock-solid seat would be seen as disastrous for Labour in the wake of previous by-election setbacks at Henley and Crewe plus at Nantwich.


Chart-topping drummer with Blur Dave Rowntree, 44, hopes to be number one again – in a by-election for a seat on Westminster City Council in London.

He is favourite to triumph for Labour in its Church Street ward stronghold.

Mr Rowntree, an animator who is also training to become a barrister, has already been selected to fight the Cities of London and Westminster seat in Parliament – held by Tory Mark Field with a 7,000-plus majority – for Labour at the next election.