MPs are to be asked to make Brexit day enshrined in law, when they finally debate the EU (Withdrawal) Bill next week.

In a sop to the hard Brexiteers on her own backbenches, Theresa May has amended the Bill so that if passed it will formally commit the UK to leaving the EU at 23:00 GMT on Friday March 29, 2019 – midnight in Brussels.

Writing in a daily newspaper, May said having the specific time of Brexit marked down was proof the Government wasn’t going soft on leaving Europe.

READ MORE: Deadline looms over Brexit divorce bill

“Let no-one doubt our determination or question our resolve, Brexit is happening,” she wrote.

“It will be there in black and white on the front page of this historic piece of legislation: the United Kingdom will be leaving the EU on March 29, 2019 at 11pm GMT.”

The draft legislation is through to its committee stage when the Bill is scrutinised line by line, and MPs and parties offer amendments.

May, who has had a bruising week, with many in her own party wondering if a leadership battle could be any worse than her staying on, is trying to show that she’s still in charge.

The Tory boss warned MPs against trying to derail the legislation.

“We will not tolerate attempts from any quarter to use the process of amendments to this Bill as a mechanism to try to block the democratic wishes of the British people by attempting to slow down or stop our departure from the European Union.”

Lord Kerr, the former diplomat who helped draft Article 50 of the Lisbon Treaty – the mechanism the UK triggered to start Brexit, dismissed May’s grandstanding, and said putting the date on the Bill did not mean the process was irreversible.

The cross-bench peer told BBC Radio 4’s Today programme that decisions such as these were being made in Westminster, and “had nothing to do with the treaty, and they have nothing to do with the views of our partners in Brussels”.

The Government is currently wading through hundreds of submitted amendments – MPs have been told there are around 300.

Meanwhile, the Holyrood Brexit committee has asked Scottish Secretary David Mundell to clarify what analysis the Government has carried out on how leaving the EU will impact Scotland. It was understood the Government had compiled 58 reports into key sectors, and that the Scotland Office fed into those accounts.

However, after MPs backed a vote forcing the Government to release the analysis, Brexit Secretary David Davis appeared to say that it wasn’t the case that there were actually 58 reports.

In her letter to Mundell, Joan McAlpine, the chair of the Scottish Parliament’s Culture, Tourism, Europe and External Relations, says she is seeking a little more clarification.

“As you know, the committee conducted extensive inquiry work on the impact of leaving the EU on Scotland,” she said.

“We would therefore be interested to know which sectors have been covered in the analysis that officials are discussing sharing with the Scottish Government and whether it is qualitative or quantitative in nature.”