A whistleblower who revealed a cruise liner was illegally dumping waste into the sea has been awarded £780,000 by the US government.

Christopher Reays discovered that oily waste was being pumped into British waters by the Caribbean Princess while serving aboard the vessel in 2013.

The Glaswegian engineer used his mobile phone to secretly take pictures and questioned other crew members before alerting authorities.

As a result of his evidence, Princess Cruise Lines Ltd has been fined a record £31m for intentionally dumping waste and attempting to conceal the crime. It is the fine largest levied for the crime in the United States.

Mr Reays was awarded $1m (£780,000) by the US Department of Justice (DoJ) as a reward for his efforts.

In a letter explaining his actions, Mr Reays said his job aboard the ship had been the "chance of a lifetime".

He said the actions of the crew had left him "hugely disappointed", however, and hoped the case would act as a "wake-up call" for the rest of the industry.

The Caribbean Princess dumped about 4200 gallons of oily waste off the coast of England in August 2013.

While the waste was being discharged, engineers aboard the ship ran clean water through its monitoring equipment to create a false record.

After investigating, Mr Reays handed his evidence over to the UK Maritime and Coastguard Agency, which passed it to the US Coast Guard.

The Caribbean Princess was intercepted and inspected when it arrived in New York in September.

Evidence emerged during the DoJ's investigation that the liner had been dumping waste since 2005.