The Indian summer has added to pressure on Marks & Spencer boss Marc Bolland ahead of the retailer’s half-year results on Wednesday.

The firm is expected to post profits down 4% to £252million in the six months to the end of September, with more unseasonably warm weather since then further clouding the outlook as shoppers delay buying jumpers and coats.

M&S is on course for a 13th consecutive quarter of falling general merchandise trading with second quarter like-for-like sales forecast to fall 3.7%, as Mr Bolland battles to revive the chain’s clothing department.

Annual profits have fallen for three years in a row and have been overtaken by rival Next which registered annual profits of £695m this year, compared to the more established rival’s full-year profits haul of £623m.

But earlier this week even City darling Next said the surprise warm weather will knock £25m off its annual profits in the current financial year.

Mr Bolland is also under pressure to show he has fixed the firm’s website, which has seen teething problems to do with customer registration and ease of use since its relaunch in February.

In July Mr Bolland said its online arm, which then had 3.2m users, was expected to start growing again by the time the retailer hits its peak Christmas trading period.

The firm hopes to register sixm users by the end of the year, the number its old website carried. Normally around 16% of general merchandise sales come through online sales.

In a bright spot for the group its like-for-like food sales are expected to lift 0.2% in the second quarter as its high-end positioning allows the retailer to avoid being dragged into the ongoing supermarket price war.

Investors will also listen out for any news about a new finance director after Alan Stewart left for Tesco earlier than planned last month to help clear up the £263m accounting scandal at the supermarket.

In contrast to M&S, fashion retailer-to-sugar conglomerate Associated British Foods is expected to unveil a sharp rise in profits for its Primark business.

The discount fashion chain will report a 28% jump in adjusted operating profit to £659m, according to brokers at Credit Suisse, as the business continues to attract shoppers and open new stores.

Primark, with its Europe-wide estate of 278 stores, has been the jewel in the crown at AB Foods and is set open its first stores in the US this year. Across the group AB Foods is set to a post group pre-tax profit up 1.4% to £1.1billion compared to a year ago, according to analysts at Numis, as it is impacted by sharply lower sugar revenues and a strong pound.

Earlier this month Primark said it would open seven stores in the US in a joint venture with rival American retailer Sears, which comes after the fashion chain announced in April it would open its first American shop in Boston before the end of the year.

Brokers at Shore Capital said the joint venture agreement with Sears could be the start of a long-term agreement with the US retailer which runs more than 2,000 stores across America.

Over the last financial year, Primark opened 1.4m sq ft of selling space in 28 new stores, the most recent being in Berlin and Bath. As well as Primark’s continued progress, AB Foods has been cheered by good growth in its grocery division after strong demand from green tea drinkers helped Twinings Ovaltine post double-digit sales growth in the year to September 13.

The division’s Allied Bakeries arm also grew revenues and profits after the launch of Kingsmill Great White boosted market share.

Meanwhile investors have been rattled by the continued impact of falling prices on its sugar division. Revenues and adjusted operating profit for AB Sugar will be substantially lower than last year, with lower volumes in north China and a currency translation impact of some £20m also to blame. The prices decline reflects the end of European Union sugar quotas in 2017, although the speed of adjustment has been faster than the company expected. British Sugar produced 1.32m tonnes of sugar compared with 1.15m tonnes a year earlier. Good growing conditions extending into the mild winter resulted in a higher beet yield and sugar content than last year.

There was a glimmer of hope for Morrisons in recent weeks after industry data suggested it was arresting the recent slide in sales.

The Bradford-based supermarket chain, which issues a quarterly trading update on Thursday, launched a new loyalty card scheme earlier this month with a promise to match prices at discounters Aldi and Lidl. It is part of a wider plan announced in March to invest £1billion in price cuts over three years as chief executive Dalton Philips battles a shrinking market share.

A price war has been forced on big name grocers as they respond to discount supermarkets and pound shops who have eaten away at their dominance. Earlier this month closely-watched data from Kantar Worldpanel showed sales at Morrisons fell 1.8% in the 12 weeks to October 12.

Its market share dropped to 11% from 11.2%.

However analysts at Shore Capital said this was an improvement on half-year results last month which saw like-for-like sales slump 7.4% with profits plunging 51% to £181m.

The broker said the supermarket’s price cuts ‘may be starting to gain some traction’ in the third quarter.

However, the big three listed supermarkets have all seen their share prices tumble as investors desert the sector. Morrisons shares have fallen by around 45% over the last year, Sainsbury’s has fallen about 40% and Tesco has tumbled by 53%.

The retailer has overhauled its antiquated IT infrastructure over the last few years which Mr Philips admitted last year had made it difficult to plan promotions.

Morrisons also made a belated entry into online grocery shopping in January, in a partnership with Ocado.

In a recent note, analysts at Moody’s Investor Services said Morrisons has taken more decisive action than Tesco to date in tackling the rising market share of the discounters.

They said: “Morrisons has recognised that price has become the number one driver for customers and that it needs to narrow the price gap with the discounters to retain market share.

“Morrison has also been more nimble in addressing costs as an offset to price reductions.”

Halfords will reveal whether the country’s warm autumn has boosted bicylce-related sales when it posts its half-year results on Wednesday.

The country’s biggest seller of bikes is expected to report six month revenues up 9.5% to £48.8m compared with a year ago, as it benefits from the weather, according to brokers at Deutsche Bank.

Worcestershire-based Halfords, which runs 465 stores and 303 Autocentres, has seen its bike sales jump in recent years in the wake of the Olympic success of champions such as Sir Chris Hoy and Sir Bradley Wiggins. The renewed interest in cycling saw large crowds line the route of the Tour de France, which held its first three stages in Yorkshire and London in July.

It is in the middle of a three-year investment programme that will see it spend £100m by the end of 2016 upgrading many of its stores and Autocentres garages.

The business, which employs 12,000 people, said in July it will create 500 new jobs as it looks to keep up with the country’s flourishing interest in cycling.

To take further advantage it has broadened its model range, particularly for women and young cyclists, and is selling more clothing and accessories.

In June it bought the bike business of Olympic gold medallist Chris Boardman, who has designed premium cycles for Halfords since 2007.

The firm reported its annual results in May, when it beat expectations with pre-tax profits up 1.1% to £72.8m.