Parliament's newest MP has been criticised for trying to win over voters from another constituency to the Conservative Party.

Conservative Trudy Harrison, who was elected in Copeland two months ago, was accused of trying to canvas postal voters for the upcoming county council elections in the neighbouring constituency of Workington, currently held by shadow environment secretary Sue Hayman.

Ms Hayman said these "unacceptable" actions had sown confusion among her constituents, some of whom had become perplexed about who their MP actually was.

The Copeland MP was in Barrow at the weekend, helping Conservative candidates in the Cumbria County Council elections. A spokesman for Barrow and Furness MP John Woodcock said she had notified him ahead of her visit.

Raising a point of order in the Commons, Ms Hayman said: "The honourable member for Copeland has written as a member of Parliament to postal voters in my constituency on Conservative-branded paper, ahead of the Cumbria county council elections, asking them to vote for the Conservative candidates.

"I know postal voters in her own constituency who have not received any such letter from her."

She went on: "I have had a number of complaints from constituents, some of whom are now confused as to who their member of Parliament is.

"My constituency office is receiving phone calls from constituents who think that this must mean that the boundary changes have gone through and I may no longer be their representative.

"As far as I am concerned, this is unacceptable."

It is common convention for MPs to notify each other if they are visiting another constituency for political purposes and MPs are not supposed to act for people who are not members of their constituency.

Speaker John Bercow said the issue was a matter of "informal agreement and understanding", which should be dealt with between MPs.

He told Ms Hayman: "I must say to you, disquieting though the experience might have been and relatively irregularly though it may occur, it is not clear to me that the honourable member for Copeland has broken any convention."