PORTSMOUTH South MP Stephen Morgan has joined 208 MPs from across the House of Commons in signing a letter to Theresa May.
The MPs are urging the prime minister to rule out a no-deal Brexit and the city Labour MP has added his signature.
The letter was organised by Tory former Cabinet minister Dame Caroline Spelman and Labour's Jack Dromey.
Dame Caroline told BBC Radio 4's Westminster Hour: ‘Crashing out of the EU without a deal will cause job losses and bring to an end the renaissance of manufacturing that we've seen in regions like mine in the West Midlands, and both Jack Dromey and I know the human interest and impact of this.’
All signatories to the letter have been invited to meet the Theresa May in Downing Street on Tuesday.
The meeting is one of a series being organised by Mrs May, who is also hosting drinks receptions for Tory MPs on Monday and Wednesday as part of an charm offensive to win support for the Brexit deal.
Mrs May has warned the UK will be in ‘uncharted territory’ if the deal is rejected in the vote, expected on January 15.
Britain is shceduled to leave the EU on March 29.
She told BBC's Andrew Marr Show: ‘What we'll be setting out over the next few days is a sort of assurances, is measures in three areas.
‘The first is measures that will be specific for Northern Ireland.
‘The second is a greater role for parliament as we take these negotiations into the next stage for our future relationship.
‘And the third, and we're still working on this, is further assurances from the European Union to address the issues that have been raised.’