Ocado ended years of speculation, this week, when it confirmed its intention to float on the London Stock Exchange.

The £200m flotation valuing the business at £1bn was a "significant milestone in the Ocado story," said CEO Tim Steiner, adding that new long-term sourcing and branding arrangements with Waitrose put the business in a position for further growth.

Ocado posted a 29% increase in sales to £230m in the 24 weeks to 16 May, and EBITDA rose 181% to £8m during the period, while operating losses were cut by 63% to £2.7m.

"Despite the difficult retail environment, we have grown at a substantial rate in the first half of the year," Steiner said.

"Our first 100,000 order week in May is a major achievement, reflecting the hard work of everyone in the Ocado team and the broad appeal of Ocado."

He added that the UK online grocery market was currently worth about £3bn per year and was expected to grow strongly.

His estimate backs figures from the IGD that suggest online grocery sales will increase from about £3.7bn in 2010 to £7.2bn by 2014.

The online grocer said as well as institutional investors, it would offer shares to all staff and any customer who had spent more than £300 with the company this year.