British police are formally considering allegations that the Conservatives broke the law during the election campaign with its use of a call centre in Wales, a Labour MP has said.

The UK’s Shadow defence minister Wayne David said the Electoral Commission had written to him to confirm South Wales Police was considering the allegations over the call centre in Neath.

Secret footage obtained by Channel 4 News suggested the Tories may have broken data protection and election laws by using Blue Telecoms to directly contact voters in marginal seats.

The Conservative Party has said it did not break the law by contracting the company, which it said was hired to carry out legal market research and direct marketing.

Speaking in the Commons, Mr David said: "She should be aware that serious allegations have been made about the use of a telephone call centre in Neath during the General Election campaign by the Conservative Party.

"I would like to tell the house that I have heard from the Electoral Commission, who have stated in writing that South Wales Police are formally considering the allegations."

His comments came during questions to Bridget Phillipson, a spokeswoman for the Speaker’s Committee on the Electoral Commission in the Commons.

The Labour MP replied: "He will know that political parties that spend over £250,000 at the General Election have six months to submit audited spending returns to the commission.

"They will need to include details of all party spending on campaigning at the election.

"It is a potential offence under the Representation of People Act for there to be paid canvassing on behalf of a candidate and any allegations will be a matter for the relevant police force to consider."

Ms Phillipson was also pressed on claims of Russian interference in last year’s EU referendum.

Ben Bradshaw, a former Labour cabinet minister, said: "Could she confirm or if not ask the Electoral Commission whether it has received allegations of illegal financial funding from Russia to elements of the Leave campaign?"

She replied: "The commission is aware of some media reports that allege there could have been Russian involvement in the EU referendum.

"These cover a wide range of alleged activities, which are beyond the remit of the commission.

"Any allegation with evidence that a registered campaigner accepted impermissible donations from Russia would be investigated in line with the commission’s enforcement policy, but I’m sure officials from the commission will be more than happy to meet with him to discuss this matter further."

Ms Phillipson also said the commission "is continuing to consider issues with some campaigners’ spending returns" in relation to the referendum.

"The commission publishes the outcome of all investigations on its website once investigations have been completed," she added.