A boat captain’s decision to ignore warnings of a monsoon rainstorm contributed to the deaths of two Britons who drowned after a speedboat accident in Thailand, a coroner has ruled.

Monica O’Connor, 28, from Sale in Greater Manchester, was on her honeymoon in Koh Samui with her husband Tim when she was killed after a wave capsized their tour boat in May last year.

Jason Parnell, 46, from Sileby in Leicestershire, who was also killed, was celebrating his first wedding anniversary with his wife Puja.

A two-day hearing at South Manchester coroner’s court heard that the pair were among 32 tourists on the boat when it capsized near a rocky stretch of coast in the Gulf of Thailand as it returned from a day-long tour. The Britons were killed along with two women from Germany and Hong Kong.

The court heard how a warning had been issued by Thailand’s meteorological department telling small boats not to sail out to sea due to a monsoon rainstorm.

The boat’s captain, Sanan Sridakeow, and operator, Limited Partnership Angthong Discovery Tour, both admitted offences including causing death due to recklessness at Koh Samui provincial court last September.

On Tuesday, the senior coroner for South Manchester, Alison Mutch, recorded a narrative verdict into the deaths.

“They died as a result of drowning, contributed to by the decision to operate the tour when a known weather warning was in force, prohibiting small boats from sailing out to sea from 24-27 May 2016,” she said.

Mutch said passengers were not given a safety briefing, lifejackets were not allocated to each passenger and the boat sailed too close to the shore.

The inquest heard that Sridakeow had been jailed for a year and fined 5,000 Thai baht (about £115). The tour operator was fined 15,000 baht.

Mutch offered her condolences to the spouses of O’Connor and Parnell, who gave evidence of the moment the boat capsized.

“I’m truly sorry that what should have been memorable holidays in the most positive and happy ways ended in the ways they did,” she said.

“I’m sure, notwithstanding the amount of time that has passed, the events of the day are etched very clearly on the minds of both of you.”