The worst incident at a Scottish Beach Awards prize-winning beach was in the vicinity of Peterhead Lido, where sewage was discharged for a staggering 483 hours last year, totalling 337 separate sewage dumps onto the beach.

There were also spills at St Andrews, Nairn and Fraserburgh.

There is reason to believe that this substantially underestimates the number of sewage dumping incidents as while there are 3,614 overflows in Scotland’s 31,000-mile sewer network, only 144 (4%) are currently monitored.

The figures for Peterhead Lido were shocking

This in contrast to England, which has 14,470 overflows of which 12,700 are monitored (89%).

Speaking in the Scottish Parliament chamber, Mr Cole-Hamilton said: “Enough to fill 19,000 Olympic-sized swimming pools.

“That’s how much sewage we know was dumped into our rivers last year by Scotland’s government-owned water company.

“I say know, because only one in 20 discharge pipes are actually monitored.

“New Liberal Democrat research that we have published reveals over 400 sewage dumps in the vicinity of some of Scotland’s best beaches last year.

“From Peterhead to St Andrews, these award-winning beaches should be protected and pristine.

"They draw tourists, families and wild swimmers.

“Like so many things on the First Minister’s desk right now, this absolutely stinks.

“So can I ask the First Minister: Will he now instruct the monitoring of all sewage discharges in Scotland? What will he do to help Scottish Water get a handle on this?

"Otherwise, how many swimming pools of poo is he content to see put on our best-loved beaches?”

Figures published by Scottish Water also reveal that in 2022 14,008 discharges into Scotland’s rivers and waterways were logged, up from 10,799 incidents in 2021. The volume of sewage overflows recorded was 47.1 million cubic meters, up from 34.9 million cubic metres in 2021.

Concern over sewage spillage at Lido beach