Ocado is joining the FTSE 100 after seeing a big jump in its share price following a year of dealmaking.
Shares in Dixons Carphone have sunk by nearly 20% after it warned of a sharp fall in profits this year.
RBS shares were barely changed in early trading, falling by 0.5% to 271p.
Wesfarmers, which bought the DIY retail chain two years ago, expects to make a loss of up to £230m ($307m).
The wave of cold weather dubbed the Beast from the East took a big bite out of B&Q’s sales in the three months to 30 April, its owner Kingfisher has said.
Shares in M&S rose 4.5% in morning trading to 305p, however, the share price is still down more than a fifth over the past year.
The FTSE 100 index closed over 1% higher at 7,859.17, comfortably above its previous high of 7,787 on 17 May.
Shares in London-listed mining giant Glencore have fallen 7% following a report of a potential investigation into its actions in Africa.
The takeover comes less than three weeks after iZettle said it would list shares in Stockholm.
Shares in online grocer Ocado have surged by nearly 50% after it struck a deal with US retail giant Kroger.