The Conservative Party has said it did not break the law by contracting a company to call voters during the general election campaign after Channel 4 News obtained secret footage of the call centre.
According to the programme, the Tories may have broken data protection and election laws by using Blue Telecoms, a firm in Neath, South Wales, to directly contact voters in marginal seats.
The Conservatives said the company was hired to carry out legal market research and direct marketing.
But Channel 4 News claimed workers may have been carrying out paid canvassing, which is banned under electoral law, because they pushed what appeared to be key Tory messages to undecided voters.
One call script quoted by the programme said: "It was reported in the Daily Mirror in September last year that Jeremy Corbyn is not concerned about the numbers of people coming to live in the UK and it was reported on Sky News this year that Theresa May has restated her pledge to reduce net migration.
"Just thinking about these reports in the media and the reports that you live in a marginal constituency that may determine who is prime minister... Does that make you more likely to back Theresa May or more likely to vote for Jeremy Corbyn?"
A Conservative spokesman said: "Political parties of all colours pay for market research and direct marketing calls.
"All the scripts supplied by the party for these calls are compliant with data protection and information law."