The Liberal Democrats said the upcoming European elections are about putting out an "alternative message" on Brexit in Lincolnshire and across the country.
Bill Newton-Dunn, who was one of the longest-serving members of the European Parliament and is a candidate at this year's elections for the East Midlands, said, while he is "not confident" about being elected, he will offer a different "argument" on the EU.
First elected in the European elections in 1979 as a Conservative, Mr Newton-Dunn served the Lincolnshire constituency in the European Parliament until 1994.
Following the abolition of the seat, in 1999 he was elected again in the newly created East Midlands regional constituency and crossed the floor to the Liberal Democrats the following year.
But, he failed in an attempt to be re-elected in 2014 during the "UKIP surge" in the EU elections which saw the party win 24 seats across the country.
Now, he is standing again for election because of what he described as a "sheer anger that Britain has gotten into".
"I think Brexit is a profound mistake," he said.
"Theresa May's deal would make us rule takers and we would still have to do was Brussels tells us, but we would not have a say and that is a really bad situation.
"I think we should remain in, it's a compromise with 27 other countries and we could fight our corner."
He added that the country should be given a vote on the proposed Brexit deal as the House of Commons shows "no sign of been able to resolve the problem".
However, if another referendum took place, Mr Newton-Dunn said he thinks the party should respect a similar result to the 2016 referendum should the electorate vote that way.
After last week's local elections, the Liberal Democrats increased their seats across Lincolnshire.
The party grew its presence on West Lindsey District Council by five seats and improved its vote elsewhere in the country.
But, Mr Newton-Dunn said he was not optimistic about winning the seat in the East Midlands again.
"I'm just going out there with the rest of us on the list to get the message out that we think the vote in 2016 was a big mistake," he said.
"There wasn't enough information, people like Boris Johnson said 'it will be glorious, it will be terribly easy'.
"It isn't, we're involved in all sorts of connections in science, universities, trade and human rights and you can't just click your fingers and get out.
"I'm not confident, but we're going to put the argument and see what happens."
The European Parliament elections will take place on May 23.