Shipley MP Philip Davies has admitted he may have slipped up as Parliament’s watchdog probes a paid-for trip he took to the Cheltenham Festival.

The parliamentary standards commissioner has started an investigation into a complaint that the Conservative backbencher failed to fully declare hospitality worth an estimated £870.

Mr Davies – a keen horse racing fan – visited Cheltenham in March 2011, as a guest of the bookmaker Ladbrokes.

However, the Tory failed to mention the gift when, seven months later, he quizzed Richard Glynn, the chief executive of Ladbrokes, during a select committee session.

Mr Davies is a prominent member of the culture, media and sport select committee, which carried out a year-long investigation into the betting trade.

Yesterday, it was confirmed to the Telegraph & Argus that parliamentary commissioner for standards Kathryn Hudson is investigating. A spokesman said: “An inquiry is ongoing.”

Mr Davies said: “I probably should have mentioned the Cheltenham visit at the committee. If I had my time again, I would refer to it.

“However, there was no attempt to conceal anything. It was simply that – seven months later – it never occurred to me at that moment. It also made no difference whatsoever to the inquiry the committee carried out or the report, which was agreed unanimously – so I don’t think I really did anything wrong.”

Mr Davies said he had offered his resignation to the committee, but none of the other ten members, including Labour MPs, believed he should quit.

A second complaint relates to an annual subscription that Mr Davies receives from Peninsula Business Services, to cover any costs relating to industrial tribunals.

The company is run by Peter Done whose brother founded BetFred, the bookmaker which took over the Tote and has 1,000 betting shops in Britain.

Mr Davies has argued it was not relevant to declare the subscription at the committee hearing, because the firm offers employment services – with no connection to gambling.