A product which increases the capacity of a wheelbarrow by up to 300% has made its inventors more than £1.3m in its first year on the market, despite the entrepreneurs rejecting an offer from two Dragons' Den millionaires.
Mike and Joe Smith appeared on Dragons' Den with the Wheelbaroow Booster in September, and were offered £50,000 for 50% of the business by Duncan Bannatyne and Hilary Devey. Mike Smith turned the offer down, saying he would give away no more than 11.5% of gardening company Greanbase.

Since then the Booster, which is a tarpaulin 'skirt' that fits around the edge of most wheelbarrow sizes, has seen orders surge. It has been developed by Mike Smith, a professional landscaper, for more than 15 years and was recently exhibited at Glee 2012, where it reportedly received "great interest" from high-profile buyers.

Homebase has reportedly placed an order of 5,000 and the Booster is also available on Amazon and Tesco Direct, as well as receiving interest from international retailers. As well as Dragon's Den, it has also been featured on The Alan Titchmarsh Show and was BBC radio 2's Innovation of the Week.

Speaking to national press after their appearance on Dragons' Den, Joe Smith said: "For the projections we gave them, we only needed to have sold 25,000 units for them to get their money back. They really undervalued it."

The Northampton-based Smiths are now struggling to keep up with demand, and predict sales of 100,000 units a year for the Wheelbarrow Booster, which retails at £12.99.

Some competition is already on the market in the form of the Planit Products Barrow Bag, a polypropylene bag designed to sit inside a wheelbarrow. Recently reviewed in Which? Gardening, the Barrow Bag claims to increase wheelbarrow volume by five times, and retails at £9.99. It is being stocked by The Garden Centre group and is also available from the Planit Products website.