Labour party canvassers have been accused of filling out ballot forms and pressurising residents as the scandal over postal voting in local elections deepens.

The allegation, which would be a breach of the electoral code of conduct, was made by a resident in a closely contested ward in Leeds.

Last week The Sunday Times reported that senior Labour figures in Leeds were instructing student canvassers in the ward to complete, collect and post the votes of elderly residents.

David Crompton, assistant chief constable of West Yorkshire police, described the Labour tactics as “extremely sharp practice”.

The police and council returning officer will consider the evidence before deciding whether to act.

The Leeds allegations add to controversy surrounding last Thursday’s elections, in which more than 100,000 ballots in Scotland were declared invalid. It is believed many people made mistakes because of the difference in voting systems for councils and the Scottish parliament. A new electronic counting system also caused delays.

Gipton and Harehills, the ward in Leeds, was won by Labour. During the week a number of residents expressed concern at the methods employed by Labour canvassers.

Tripta Sharmer, 72, said on Tuesday she was visited by a party worker who filled in part of her form then posted it for her. “I always vote Labour,” she said. “Someone from Labour asked me who I was voting for and I told him. He said there was no need to go to the votes outside [at polling stations] because you can sit here and I can take your vote and it will go by post. He filled it in, I did the two signatures.”

One 74-year-old disabled resident said she was shocked when a Labour canvasser offered to post her vote. She said: “I find it amazing that they are targeting vulnerable people like this.”

Others, however, were happy to have the assistance. Beryl Clough, 47, who is disabled, gave her postal vote to a Labour canvasser. “I was happy for him to send mine because I can’t walk very far. I didn’t think there was anything wrong with it,” she said.

Labour won the seat from the Liberal Democrats by nearly 1,000 votes. The Liberal Democrats are now considering whether to take legal action to quash the result.

Yesterday Keith Wakefield, leader of the Labour group on Leeds council, denied improper conduct. He was recorded at a meeting in which canvassers were told to help elderly voters to complete postal ballots.

He said: “The Labour party is happy that any investigation takes place.”

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