Standing nearly 2m tall (6ft 5in) on his hind legs and tipping the scales at 124kg (19st 10lb), Samson is enough to make even the most intrepid mailman think twice.
The Newfoundland- Great Dane cross is so big he needs to wear a coat intended for a pony when it is wet and needs an outsize collar to fit his 73cm (29in) neck.
He costs owners Julie and Ray Woods £60 a month to feed, living on a diet of dried food and turkey legs, and requires four 3km (2miles) walks a day.
But the animal described by the Woods as a 'gentle giant' is only three years old – and his owners say he is still growing.
Samson was acquired from an RSPCA centre when he was six months old and already more than 100kg (16st).
Meet an even larger dog after the jump.
Don't let its name fool you. Tiny, the hulking hound, stands at 2.2m (7ft 3in) on his hind legs – an impressive 25cm (10in) taller than Samson.
Unlike Samson, a Newfoundland- Great Dane cross, Tiny is pure Great Dane, towering over his 1.85m (6ft 1in) owner Iain Newby.
Mr Newby, 40, said:"I've never seen a bigger dog than Tiny. He's got 40in legs. I'm a 32in leg. He's bigger than some horses in the fields we walk past. It's funny when we are out walking and someone turns round – and almost jumps out of their skin. I get some funny looks when I'm calling him back to me, people look as if to say, "Tiny"? We used to have a dining room but now we have a Tiny room. He sleeps on a sofa."
Tiny – found at a rescue centre – lives with Mr Newby, wife Lisa, 34, and sons Jack, three, Harry, two, and one-year-old Bryce in Great Wakering, Essex.
Sources: Metro & Metro
Tags: Britain | Biggest | Dogs