Broker upgrades have fuelled optimism surrounding Marks & Spencer in recent weeks, although this will come crashing down on Tuesday if evidence from the second quarter fails to point to a bottoming out in its sales decline. It should be the biggest test yet for chief executive Stuart Rose, as autumn ranges will reflect his ideas rather than the designs of previous management. While tough trading conditions will cloud the outcome, any suggestion that the worst may be over for the retailer is likely to reinforce views in the City that M&S is worth the 400p a share that Bhs owner Philip Green was willing to pay last year before he abandoned his £9.1 billion takeover campaign. At its last update, M&S said like-for-like sales fell 5.4 per cent in the 14 weeks to July 9, with the biggest falls in clothing and homewares. At WH Smith, chief executive Kate Swann will look to buy more time for the retailer's recovery strategy when she presents annual results to analysts and investors on Thursday.