They may bring joy to many in later life, but a survey has revealed that Britain's grandchildren are causing an astonishing £300 million of damage every year at their grandparents' homes.
A survey of the nation's long-suffering grannies and granddads has revealed that looking after those beloved youngsters is costing them dear.
The little darlings are wreaking havoc all around their grandparents' cherished homes.
The study – which marks National Grandparents' Day today – reveals that some grandparents have suffered smashed television screens, broken beds and, in one case, even had valuable pet fish killed.
But top of the list of damage is spilt food and drink on carpets and soft furnishings, which accounts for nearly two-thirds of all carnage caused by visiting grandchildren, followed by drawing and painting on walls and, in third place, broken ornaments.
The average cost to house-proud grandparents is more than £85 per room, with living rooms witnessing 30 per cent of incidents compared to 17 per cent in gardens and 12 per cent in kitchens. And, unsurprisingly, boisterous boys cost almost 20 per cent more than girls, with the worst age group for costly damage being four- to six-year-olds.
Dame Esther Rantzen, 78, who is spending today with two of her grandchildren, said: 'I've detoddlerised my flat. Anything of any value gets put out of reach.
'You can't put a price on the joy they give. I regard any creative additions to my home as increasing its value.
'I think you have to recognise that it's up to you to protect your property if you care about it and, if it's fragile, get it out of the way.
'Luckily, my grandchildren have never broken anything, nothing at all. But my heart really goes out to the families where grandchildren don't have access to their grandparents, because I think it is such a crucial relationship.'
The research was conducted by David Wilson Homes and was based on responses from 1,000 grandparents caring for children aged from one to nine years.