The DUP is to reveal the identity of the donor that supplied the cash for the party's pro-Brexit advertising campaign.

Prior to last year's EU referendum the party took out an expensive wraparound advert with the London freesheet the Metro, reported to have cost £250,000.

The four page ad carried the message "take back control" urging people to vote leave. As well as in London some have reported seeing the advertisement in the north of England. It was not distributed in Northern Ireland.

The DUP has faced mounting calls to reveal how much it received and from where.

Edwin Poots, in a BBC Talkback debate, said the party was working on revealing the size of the donation and the donor this week.

Given secrecy rules around Northern Ireland party political donation rules, those who funded the campaign have not been revealed.

Donations to political parties here are kept confidential for fear of identifying donors. But other political parties have demanded that the DUP clarify who funded its "lavish" pro-Brexit advertising campaign.

Open democracy campaigners claimed the rules meant "dark money" could be funnelled through local politics and into the British system.

MP Jeffrey Donaldson said: "We are looking into it at the moment with the Electoral Commission.

"We will make our position clear once we have gone through all of the issues with the Electoral Commission."

A DUP spokesperson added: "Arlene Foster has asked our campaign director for the EU referendum to work to ensure maximum transparency. We are working to ensure this happens as soon as possible.

"We are proud of the role played by the DUP in supporting a vote to leave the EU. All the necessary returns have been submitted to the Electoral Commission and we are working to ensure the maximum amount of information can be published as soon as possible."

However the Electoral Commission said discussion with the party had not taken place.

In a statement it said: "The Electoral Commission has had no discussions with the DUP on the issue of publishing donor information.

"The Commission is legally bound to retain confidentiality about donations to political parties in Northern Ireland. Whether parties or donors choose to make this information available is a matter for them.

"In that event, the Commission remains bound by this legal requirement for confidentiality and would therefore be unable to comment."

A UK Government spokesman said the Secretary of State is "keen to make progress" on the issue but that it would not be before the March election.

"The Secretary of State wrote to the Northern Ireland parties in January 2017 seeking their views on moving to full transparency," the spokesman said.

"He remains keen to make progress on this issue and is currently considering responses received from the parties. An announcement on a way forward will not take place until after the election, in line with the usual pre-election protocols."

Last week Arlene Foster confirmed to the BBC a donation was made to the party, but she could not recall the amount.

On the UTV leaders' debate, Mrs Foster said: "They (the funds) are from an organisation in England that wants to see the union kept and make sure we can have a United Kingdom because it was a national vote..."

Belfast Telegraph