THERESA May appears set on a collision course with her Scottish Conservative MPs over the option of extending the Brexit transition period.

Brexit Secretary Dominic Raab has admitted the UK Government is considering an extension.

“I’m open-minded about using a short extension of the implementation period – let’s say three months,” he said.

While Mr Raab made clear that any extension would be contingent on a time-limited backstop, the prospect will nonetheless alarm Scottish Tories, who feel any decision to prolong the transition period would be seen as a betrayal of Scotland’s fishing industry.

After initially being told the UK would take back control of its fishing waters on Brexit Day next March, the industry was then informed it would have to wait until the end of the transition period in December 2020 to do so.

Now, however, even a further extension by three months would mean it would have to shadow the hated Common Fisheries Policy[CFP] for another year because quotas are set in December for the following 12 months.

Last week, Scottish Secretary David Mundell contacted Number 10 to express his concerns, insisting that any extension to the 21-month transition period had to have an opt-out for the fishing industry from the CFP.

Yet, Scottish Tory MPs have privately admitted it would be highly unlikely the EU27 would agree to this.

Some of them have already warned the party whips that they could not accept a transition extension without the fishing exemption and would be prepared to vote against the Government, even possibly voting down the Chancellor’s Budget, such is the strength of feeling.

Douglas Ross, the Tory MP for Moray, is the latest Scottish Conservative backbencher to air his concerns, telling the BBC's Sunday Politics Scotland programme: "I could not support a deal that would include staying in the Common Fisheries Policy beyond December 2020."

He added: “What's important is that we send out a very strong signal to everyone who is negotiating on behalf of the UK that this is an issue that is extremely important for our Scottish communities that we represent. We cannot have the CFP."

Mr Raab called for goodwill and "a bit of oomph on both sides" to get the exit deal over the line.

He went on to say that any backstop arrangement to keep the Irish border open could not be permanent, yet he did not mention there would have to be a specific end date written into an agreement.

The Secretary of State stressed: “It would be rather odd if we ended up in that bridging temporary mechanism without a route out. It could be time-limited, there could be another mechanism.

“I probably wouldn’t call it an ejector seat but there needs to be something which allows us to control how long we are there for to avoid any sense that we are left indefinitely in a sort of customs union limbo. That wouldn’t be acceptable.”

Mr Raab also stressed that any further delay in getting a deal beyond the end of November could lead to “practical implications” at Westminster for getting any agreed deal through the parliamentary process.

He explained: “If it went any distance beyond that, we would have a problem with implementing a deal and it would almost be the worst-case scenario – we had a deal but we couldn’t implement it in time.”

Today, the Prime Minister is due to face more angry voices when she makes a Commons statement on last week’s EU summit, which was supposed to be the “moment of truth” for the Brexit deal but ended up making no real progress.

She will make clear “the shape of the deal across the vast majority of the Withdrawal Agreement is now clear".

Some “95 per cent" of the Withdrawal Agreement and its protocols is settled, including agreements on Gibraltar and the military bases in Cyprus that were concluded in the last three weeks.

On the Irish border issue, Mrs May will say: “The commitment to avoiding a hard border is one that this House emphatically endorsed and enshrined in law in the Withdrawal Act earlier this year.

“As I set out last week, the original backstop proposal from the EU was one we could not accept, as it would mean creating a customs border down the Irish Sea and breaking up the integrity of the UK.

"I do not believe that any UK Prime Minister could ever accept this. And I certainly will not.”

Ian Blackford, the SNP leader at Westminster, demanded that Mrs May set aside Commons business today to hold a full day’s debate on Brexit, saying she could “no longer duck and dive parliamentary scrutiny”.