Fake letters purporting to be from the SDLP leader, seeking financial support for an indebted Westminster campaign, have been sent to voters.

Colum Eastwood branded it an organised dirty-tricks ploy intended to poison the democratic process.

Police are investigating.

The Foyle candidate said: "The people of Foyle know that this is a close race between myself and Elisha McCallion.

"Voters should make up their minds on our records, not a campaign of dirty tricks."

He is bidding to overturn Sinn Fein candidate Ms McCallion's wafer-thin majority from the last election.

The fake letter said it was seeking financial support for Mr Eastwood's election campaign, which it wrongly claimed had a £20,000 shortfall.

It mentioned donations of up to £5,000, methods of transferring money, and called for "speedy action".

Mr Eastwood said: "I am disgusted that fake letters purporting to be from me have been delivered to houses in Derry.

"Let me be clear, these letters are not from me nor are they from anyone associated with my campaign.

"This is an organised attempt to lie to the people of Derry, to poison our democratic process and those responsible should be ashamed."

An SDLP spokesman added that the letters were a breach of electoral law.

"The SDLP has referred this matter to the Electoral Commission and to the Police Service of Northern Ireland (PSNI) for investigation," the spokesman said.

In 2017, Ms McCallion took the Foyle seat from the SDLP's Mark Durkan by 169 votes.

Ms McCallion said: "I condemn any fake election material from any source. I want to see this election campaign conducted in an open and democratic way."

Mr Durkan had been Foyle MP for 12 years and the party had held the seat for decades.

Mr Eastwood is promising to take up his Westminster seat if he wins, to oppose Brexit, in contrast to Sinn Fein's blanket practice of abstaining, including during key votes on the EU departure.

Derry and Strabane PSNI district commander Gordon McCalmont said: "Police received a report just after 11.30am today about a letter circulating in the Foyle area in relation to the up and coming election.

"Inquiries are under way, and we are liaising with our colleagues in the Electoral Office."

He appealed for anyone with information to contact police.