Nineteen MPs have written to Culture Secretary Lisa Nandy MP, urging her to stop the Gambling Commission from implementing betting affordability checks that they fear will cause a £250m black hole that could devastate the industry. They warn that the move prompts the risk of 44,000 people being pushed towards illegal markets to avoid the regulatory checks.

The open letter was sent to Ms Nandy ahead of the Gambling Commission's Board meeting on Thursday this week, where it is feared Labour's plans to introduce state-mandated affordability checks will be rubber-stamped.

However, the betting industry is aiming to intensify its pressure on the Government and the Gambling Commission by raising the prospect of legal action against the checks with the Betting and Gaming Council.

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This follows a campaign by the horse racing and betting industries, highlighting the potentially devastating impact on the sport's finances caused by affordability checks. The Gambling Commission's pilot of the checks found that Credit Reference Agencies produced different results for the same customer due to unreliable data, meaning operators would still need to request personal financial documentation.

The Betting and Gaming Council warned that checks in their current form would result in over 44,000 horse race bettors moving to the illegal market, leading to a £13m loss of vital Levy funding for British racing. The checks could cost racing £250m in the first five years alone.

The 19 MPs have criticised the Government's decision to give control of affordability checks to the Gambling Commission and say the move comes despite "a clear promise" by the previous Ministerial team that the checks would only be implemented if they were "fully frictionless" and if an independent evaluation agreed with the Commission's findings.

Last week a key adviser to the Government on affordability checks, Dr James Boyes, dramatically quit his position saying that plans to roll out the controversial policy without proper scrutiny were "clearly unacceptable".

Signatories to the letter include MPs from five separate political parties and include the MPs for Aintree (Dan Carden, Lab), Ascot (Jack Rankin, Con), Epsom Downs (Helen Maguire, LD) and Newmarket (Nick Timothy, Con), calling into question whether affordability checks have the "widespread" support that the Government claims.

British Horseracing Authority director of communications and corporate affairs Greg Swift said: "We are grateful for the tireless support of racecourse MPs who have recognised the existential threat to their constituencies posed by these checks.

"The damaging blow to racing's finances will lead to job closures in their areas as well devastate a much-loved sport that is beating heart of their communities.

"This is not the first intervention by racecourse MPs and their opposition to these checks is spread across several parties.

"Racing communities depend on a successful, thriving and financially viable sport and the Government publicly recognised that in the last Budget.

"The checks about to be implemented are in direct contradiction to the Government's public messages of support for racing and so we again call on it to stop the checks and think again."

Racecourse Association (RCA) chairman Wilf Walsh added: "The financial damage inflicted on British horseracing by affordability checks has already been felt, and this will be exacerbated once the pilot becomes policy. We again call on the Government to intervene and pause the pilot programme to allow for a thorough and transparent evaluation of the evidence."