Troubled Tesco has cut its full-year profit forecast to £2.4bn from £2.8bn and slashed its dividend by 75% citing "challenging trading conditions".

It is the third time in three years that Tesco has lowered its expectations, while fighting a seemingly losing battle for market share.

The UK's biggest retailer issued a profits warning in July and at the same time announced its chief executive Phil Clarke was to be replaced by new boss, Unilever veteran Dave Lewis, who is now set to start work on Monday - a month earlier than scheduled.

Chairman Richard Broadbent said: "Our new chief executive, Dave Lewis, will now be joining the business on Monday and will be reviewing every aspect of the group's operations. This will include consideration of all options that create value for customers and shareholders."

Tesco also said it will cut costs: capital expenditure will not be more than £2.1bn, which is £400m less than planned. It translates to £600m in cost savings on last year which will hit its IT budgets and slow down store refurbishments.

Broadbent added: "The board's priority is to improve the performance of the Group. We have taken prudent and decisive action solely to that end."

Tesco has dominated the UK high street for years but is now under attack from discount stores like Aldi and Lidl, which recently said it plans to create thousands of UK jobs as part of expansion plans.

By contrast, Tesco has this year revealed its worst figures for decades.