Supermarket group Sainsbury's has reported a 15% fall in first-half profit, blaming the combined impact of the phasing of cost savings, higher marketing costs and tough weather comparatives with last year which impacted on sales.

The 150-year old group did, however, forecast that second half profits would benefit from the annualisation of last year's staff wage increase and a normalisation of marketing costs and weather comparatives.

This implied it was on track to make analysts' profit consensus for the full 2019-20 year. 

The first half profit fall comes as Sainsbury's tries to rebuild confidence in its strategy following a botched attempt to take over rival Asda. 

Britain's competition regulator blocked the agreed £7.3 billion deal in April and Sainsbury's shares have fallen 34% over the last year. 

In September, chief executive Mike Coupe put cost cutting and paying off debt at the heart of a new plan designed to show Sainsbury's can prosper on its own. 

The group said it made an underlying pretax profit of £238m in the 28 weeks to September 21. 

That compares with analysts' average forecast of £232m but is down from £279m made the same time last year. 

Group sales fell 0.2% to £16.86 billion, with like-for-like sales, excluding fuel, down 1%. 

Before today's update analysts were on average forecasting a 2019-20 pretax profit of £584m, down from £601m in 2018-19. 

Sainsbury's reported a statutory pretax profit of just £9m for the first half. That reflected £229m of one-off costs, the bulk of which follows a review of its store portfolio.