‘Not any old vermin’: rats numbers are on the rise thanks to global heating – and poison may not be the answer

Robert Corrigan has been dealing with the smart' rodents all his life - and believes there are better solutions to deal with the growing infestation in the world's cities

The rodents have paid for every single bill I've ever had - every mortgage, every car payment, every pint of Guinness," says Dr Robert Corrigan. It's been a great ride and I'm still at it."

New York-based Corrigan is one of the most respected voices in the world of rodentology. Now in his 70s, he has devoted his entire adult life to studying rats and our relationship with them.