By Dan Newling

Last updated at 20:40 13 August 2007

Less than a year ago he stood chastened as the

Dragons' Den judges gave him a typically fiery dressing down.

Now inventor Rob Law is having the last laugh after a product rejected as 'worthless' on the BBC television programme for budding entrepreneurs has proved a huge commercial hit.

Mr Law, 29, from Bath, spent 11 years - and £17,000 of his own money - refining his design for a wheelie suitcase which doubles up as a child's ride-on toy.

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The plastic Trunki case is designed to allow youngsters aged three to six to take their own bag on holiday - and to sit on it when they are tired.

But when Mr Law appeared on Dragons' Den last September, he was given short shrift by the famously stern panel of investors.

Businessman Theo Paphitis, chair-man of the Ryman chain of stationers, ridiculed the product after managing to pull off one of the straps. His colleague Deborah Meadon, head of a holiday firm, declared bluntly that there was no market for the case.

And the notoriously brusque tele-communications tycoon Peter Jones declared: "I meet people like you all the time - you think you have something. I tell you, you don't."

He added: "Within seven days I could do a better job than that. Your company is currently worthless."

The panel declined Mr Law's offer to give up 10 per cent of his fledgling company in return for a £100,000 investment - an offer which valued the firm at £1 million.

However, it now appears that the experts missed a valuable trick.

After a succession of positive press reviews, Mr Law has sold 85,000 of his Trunki suitcases. It is marketed in 22 countries via a network of distributors.

Retailing at £25, it is one of the top-selling luggage items at John Lewis department stores and has proved a hit at Mothercare, Fenwick and Debenhams.

Yesterday, Mr Law said: "When I went on to the programme I was full of confidence that I was going to get the investment I needed.

"But they ripped me to shreds - I was absolutely gutted. They were rude and obnoxious and just focused on the strap, which was actually something that was quite easily fixed.

"I was terrified that by appearing on the programme I may have ruined my company before it had even started. But afterwards we had loads of hits on the website from people who said they thought it was a brilliant idea.

"Now I am absolutely delighted to have proved the Dragons wrong. It just goes to show you should never give up."

Mr Law also revealed that during filming he managed to sell two of the suitcases to Australian panellist Richard Farleigh, who wanted to invest £100,000 in return for half of the company. But Mr Law rejected the deal.

He declined to say exactly how much the company - which is 100 per cent owned by him - is now worth, but said that it was more than £1 million.