An open letter calling for reform of the UK government’s Sri Lanka travel advice has received “overwhelming support” within days of being published.

The letter, which came out on Friday, January 12, was signed by more than 35 MPs, peers, travel providers and businesses.

It labelled the current travel advice on the safety of UK nationals abroad by the Foreign, Commonwealth & Development Office (FCDO) as “overly harsh”, “outdated” and “synthetic”. It claimed the advice was no longer fit for purpose, and warned it could damage travel to the destination and its tourism industry, which employed more than 380,000 people last year.

Sam Clark, managing director of Sri Lanka specialist Experience Travel Group, which penned the letter, said the letter had already had an impact.

He said campaigners were now asking MPs to put the points outlined in the letter directly to the foreign secretary.

He said: “We have had overwhelming support from campaigners and parliamentarians, and we are asking MPs to put these points to the foreign secretary directly.

“We very much hope that Lord Cameron or his junior ministers will respond constructively and review both the Sri Lanka advice and the advice regime more generally.”

Campaigners are unhappy with the contention in the advice that violent unrest could happen anywhere in Sri Lanka at short notice and the appeal to UK travellers to avoid crowded places, which Clark said was “particularly excessive and unfair”.

The letter has been signed by four members of the Sri Lankan All Party All-Party Parliamentary Group, Sri Lankan minister of tourism Nishad Wijetunga, the president of the Sri Lankan Association of Inbound Tour Operators (Slaito), and former captains of the Sri Lankan cricket team Kumar Sangakkara and Mahela Jayawardene.

Clark said the advice had been in place for some years but updates in recent weeks to the advice online were “inadequate” and contained “all sorts of dire warnings which are, at best, outdated if they were ever justified at all”.

Organisers of the letter are now bringing key figures from the Sri Lankan community, from politics and the media, together at an event at the end of the month to keep up the campaign’s pressure on government to change its advice.

“We are determined to see this through and are well supported in parliament so ministers cannot ignore the issue forever,” added Clark.

He fears the wider implications could mean travellers ignoring the advice altogether while for first-timers it acts as a deterrent.