Britain's biggest retailer Tesco announced on Monday it will create 20,000 new jobs over the next two years, despite a recent set of poor results. The supermarket giant will generate the positions through investment in customer service, refreshing existing stores and opening new ones. The retailer posted poor sales during the vital Christmas trading period and warned that its annual profits growth would be towards the lower end of market expectations, blaming "challenging" conditions at home and elsewhere. Tesco was recently embroiled in controversy when activists targeted its involvement in a government scheme in which unemployed youngsters completed up to eight weeks unpaid work for the company in return for their jobseeker's allowance. Opponents accused Tesco of using "forced labour", and the retailer pulled out of the scheme, forcing the government to rethink the initiative. Tesco stressed that Monday's announcement demonstrated its "focus on giving opportunities to young people currently unemployed." "As well as providing a crucial first rung on the career ladder for each individual, this move will be a major step in tackling the current record levels of youth unemployment," the supermarket said in a statement. Prime Minister David Cameron called the announcement: "a massive confidence boost for the UK 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," he added. Tesco UK CEO Richard Brasher said major businesses "have a big responsibility to step forward" and provide employment as Britain's economy struggles to recover from recession. Tesco is the country's largest private sector employer with over 290,000 staff.