Gambling firms staged a charm offensive during 2016, spending more money on adverts and stepping up the hospitality they offer MPs, who are considering a regulatory crackdown.

The industry has come under the spotlight amid concern about its commitment to curbing problem gambling and fears about the influence that daytime TV adverts have on children.

The increased scrutiny culminated in a government review of betting firms’ social responsibility, including controversial fixed-odds betting terminals (FOBTs), often dubbed the “crack cocaine” of gambling for their addictive nature.

The parliamentary register of members’ interests, which details the value of gifts and donations received by politicians, reveals that major bookmakers and horse racing firms quadrupled their efforts to entertain MPs ahead of the review.

Politicians enjoyed the largesse of the gambling world on 33 separate occasions last year, accepting tickets worth thousands of pounds to racing and football events.They accepted nearly £20,000 of hospitality, including tickets to Ascot, the Derby and the Grand National.

The two biggest beneficiaries were Conservative MPs Laurence Robertson, and Philip Davies, who was referred to the MPs’ ethics watchdog in 2013 over his links to the gambling industry.

Davies accepted £4,720 of hospitality from the gambling industry in 2016, while Robertson enjoyed entertainment worth £5,166.

On their basic salary of £74,962, it would take an MP nearly a month to earn enough to pay for £5,166 of hospitality out of their own pocket.

Other notable recipients include former SNP leader Alec Salmond – who was given a badge worth up to £1,000 by the Racecourse Association permitting entry to certain racecourses – and secretary of state for international development Priti Patel.

She was given two Grand National tickets worth £2,000 by Jockey Club Racecourses.

The amount spent on MPs – during a year in which the threat of increased regulation has loomed large – was a major increase on 2015, when gambling and racing firms hosted MPs just nine times, to a total value of less than £5,000.

A spokesman for the Campaign for Fairer Gambling, which campaigns for FOBT maximum stakes to be reduced from £100 to £2, said: “Those MP’s who accept the bookies’ free entertainment must surely realise what this is really about and why all of a sudden they are splashing the cash on them.

“They are trying to garner what support they can for their £100-a-spin machines and stave off what looks like an impending clampdown by the government.

“Our campaign looks forward to finding out where the 33 MPs who have accepted hospitality stand on the issue of the bookies’ addictive machines.”

Last month Carolyn Harris, Labour MP for Swansea East, called for the maximum stake on FOBTs to be reduced in her capacity as chair of the all-party parliamentary group on FOBTs.

She said: “Interestingly I’ve never been offered any hospitality, not that I would expect to be.”

There is no suggestion that any of the named MPs have been unduly influenced in their decision making by gifts received.

The UK’s booming gambling sector also continued to ramp up its spending on TV adverts.

Excluding lotteries, gambling firms had spent £94.4m on TV adverts by the end of October, according to data analysis firm Nielsen, putting them on course to beat the£118.8m spent in 2015.

Including lotteries and spending in the print media and billboards, betting firms had spent £211m by October, with figures for the full year not due to be released until February.

The amount of gambling advertising on TV has triggered concerns among politicians and campaigners about the potential impact on children of daytime adverts for gambling, which are permitted alongside sporting events.

The gambling industry also ramped up its lobbying efforts with the Back Your Local Bookie campaign, launched by the Association of British Bookmakers (ABB).

The ABB tweeted about the campaign in mid-October, which coincided with the Department of Culture, Media and Sport launching its call for evidence on gaming machines and social responsibility.

The campaign website includes an automated form that allows people to put their name to a letter to their local MP, worded by the ABB.

It reads: “I’m tired of how bookmakers are constantly misrepresented, and I’m concerned about the impact of any further regulation on bookies.

“Betting shops are closing at a rate of over 100 per year and with that local authorities are losing yet another business rate paying retailer from their high streets. And without bookies, our high streets will continue to suffer a decline in footfall.

“The potential for further regulation will only hasten these closures. My local bookie is a sociable, fun meeting place, with great staff, and I want it to stay that way.”