A North-east game designer who promises 1million to the first person who solves his mind-bending puzzle before the end of September has revealed that his next puzzle will carry a prize of 5million.

Christopher Monckton, 47, from Crimonmogate Estate, near Fraserburgh, will officially announce plans for a follow-up to the hugely-successful Eternity game at the International Toy Fair in London on Monday.

The gambling gamesmaster told the Press and Journal yesterday that if no one has successfully completed Eternity by September 30, then he will release Eternity 2, with a 5million award for its completion.

The Eternity game has been hailed as one of the biggest puzzle crazes to hit the shops since the Rubiks Cube was in its heyday. Experts reckon the first Eternity game, released in the summer last year, is so tricky it could take at least four years to complete.

Rumours were around on the Internet at the tail end of last year, that some people were on the verge of completing the game. These claims forced Mr Monckton to put his neo-classical palace on the market.

He explained just why he decided to raise the stakes with Eternity 2 despite facing months of uncertainty to cover his original gamble.

"When you are an entrepreneur you have to take gambles and you're always looking for the one that will make you rich.

"Even if you get down to piece 208 of 209 and it doesn't fit, you have to start all over again. Some people say they are close but they don't really know the truth."

He added: "Eternity is one of those games that if you get it right it could prove very positive. At the end of the day, you win some and lose some. I just hope it keeps selling and maybe I won't have to sell my home."

Should someone crack the puzzle before this year's date then Mr Monckton claims his palace, set on a 200-acre estate, will need to be sold off.

He concluded: "I am confident that Eternity will prove too difficult to complete by September 30."