Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Lord Randall tucking in to some crayfish at a pop-up in Bermondsey Restaurants should put invasive species including Muntjac deer and crayfish on the menu, a peer has said as he urged the British public to eat these ‘guilt-free’ foods.Lord Randall of Uxbridge, who used to advise former Prime Minister Theresa May on environmental issues, said eating crayfish is a “great idea” to help our aquatic environment, where the invasive crustacean devastates native fish and amphibian populations.He told The Telegraph: “Crayfish in particular are a real nuisance. I had a fun evening down with the kids at a pop -up in Bermondsey [London] enjoying my crayfish.”They are particularly tasty and more sustainable than eating prawns which are farmed in the Far East – they are actually connected with modern slavery.”One of the tastiest deer around is Muntjac, which is an invasive species too. “Let Britain eat its way out of invasive species, I’m up for the job.” Muntjac deer, shooters argue, can be a guilt-free alternative to other red meats.Tim Bonner, the CEO of the Countryside Alliance, explained: “It does a huge amount of damage to woodlands across lowland England, we’ve got quite a significant problem with browsing of low-lying vegetation in woodland which supports a lot of ground-nesting birds. “They taste delicious, they are the most sought-after of all the venison species, though there’s not very much meat on them – they’re tiny. They’re also quite a challenging quarry as they’re so small. We need to encourage as many people as possible to hunt them as they have such a disastrous effect on biodiversity.”He added that the Canada Goose is another example of an invasive species causing nuisance – but it is not legal to sell their meat. Shooters who kill the geese, however, have been known to enjoy them in casseroles and stews.Restaurants in London are catching on to the trend. Ivan Tisdall-Downes, who runs Native in Borough, has flooded his menu with invasive species.These include the signal crayfish, pennywort, pineapple weed, grey squirrel, Muntjac deer, Wild Fal oysters, Darwin’s barberry and the Alexander plant.