Voters in Wells have been urged to lobby Tessa Munt MP against Government proposals to redefine marriage.
Activists for the Coalition for Marriage (C4M) group, which opposes the Government's plans, are targeting 65 key seats throughout the country. Last week they were leafleting voters on the streets of the constituency where Ms Munt holds a majority of only 800.
C4M says it has 841 supporters living in the Wells constituency, and 625,000 supporters nationwide.
C4M's national campaign director, Colin Hart, said: "Our local activists are fired up to make sure voters have their say.
"We have identified Wells as a key seat, together with 64 others nationwide.
"MPs can expect local voters to be pressing them on where they stand on the redefinition of marriage.
"These plans are unpopular and divisive. The voters were ignored by the politicians, this was in no party's manifesto and the public consultation was a sham. The Government should concentrate on reviving the economy and delivering better public services, that's what ordinary people want – not playing politics with marriage."
The Government hopes to introduce very soon a Bill to the House of Commons to redefine marriage, but 130 Tory MPs have already said they'll vote against it.
Polls show 70 per cent of the public want to keep marriage as it is, and a national petition against the plans has attracted more than 620,000 signatures.