Tesco Plc, Britain's biggest retailer, plans to open new stores and create 20,000 new jobs in the UK over the next two years as it battles back from a profit warning earlier this year and seeks to tackle a drop in UK market share.

Britain's biggest private sector employer said as part of the plan it would update existing stores, open new outlets and would look to make a significant investment in customer service.

It also said it would look to take on unemployed young people and expand its apprenticeship program to provide 10,000 apprenticeships.

We will invest in more staff on the sales floor at busy times, (provide) greater expertise and help in the crucial areas of fresh food, and enhanced quality and service across our stores at all times, Richard Brasher, Tesco's UK chief executive, said in a statement.

With youth unemployment at record levels, we're determined to target many of our new jobs at young people currently out of work, so that in this difficult jobs market those who need help the most will get it.

Tesco's share of the British grocery market fell to levels not seen since 2005 last month, according to industry data. Market research by Kantar WorldPanel said Tesco's market share fell 0.6 percent year on year to 29.7 percent in the 12 weeks to February 19.

Tesco, which issued its first profit warning in living memory in January, did not specify how much it would invest in the scheme or how many new stores it would open.

The unemployment rate runs at 8.4 percent, data from the Office for National Statistics showed last month.

The politically sensitive number of young people without a job ticked down to 1.038 million in the three months to December, taking the unemployment rate for 16- to 24-year-olds to 22.2 percent. Youth unemployment rose above the 1 million mark last November for the first time since comparable records began.

Prime Minister David Cameron said Tesco's move was a massive confidence boost for the economy.

Their commitment to creating jobs and opportunities for young people at what is a difficult time for the economy is fantastic news for the UK as a whole and for those people they will help into work, said Cameron.

The government has been relying on private firms to create enough jobs to make up for the estimated 700,000 jobs it is cutting in the public sector as part of its austerity program, aimed at erasing the country's huge budget deficit over the next five years.

(Reporting by Rhys Jones; Editing by David Holmes)