There were once fears its distinctive booming sounds would be lost forever.

But new figures have shown that the bittern, once at threat of extinction, is very much back – with numbers in East Anglia at a record high.

Since 2006, there has been a year-on-year increase in the number of bitterns making their home in the region.

A survey has revealed that this year there were 83 males, compared to 76 in 2017 – which the RSPB says is a positive sign that bitterns are back from the brink and thriving.

Twenty years ago, there were only 20 in the whole of Britain.

Yet despite the continuing rise, the RSPB is calling on the laws that protect bitterns to be safeguarded post-Brexit – as they have benefited from European Union laws, as well as EU-funded projects.

Martin Harper, RSPB global conservation director, said: “With their foghorn-like song and cryptic yet distinctive plumage, bitterns are one our most charismatic birds.

“Their astonishing recovery from the brink of extinction is a real conservation success story, but we must ensure it isn’t done in vain.

“As the UK has voted to leave the EU, we must safeguard their future as a breeding species in the UK by bolstering the laws that protect nature and replacing the funds that will be lost.”

Jeff Knott, RSPB regional director for the East of England, said: “It’s brilliant to hear that we’ve had a record-breaking 83 booming bitterns in East Anglia this year – a number certainly testament to the hard work put in by nature reserve teams across the region to safeguard this special species for the future.”

Simon Wotton, RSPB senior conservation scientist, added: “We count bitterns by listening for their distinctive booming call, and every year more and more bitterns are making newly created or restored wetlands their home and to raise young.

“The recovery of this elusive bird is a remarkable conservation success and shows what can be achieved through targeted efforts to restore and create more of their favoured habitat.

“To go from being on the brink of extinction to having close to 200 booming males in 20 years – at a time when many other species are in decline – highlights how effective this project has been.”