ONLINE retailer Amazon has warned of a sales slowdown in the run-up to Christmas as it turned the screw on high street rivals in the UK by cutting delivery costs.

Amazon is offering to deliver gifts and products for free if customers spend at least £15 on its UK website - down from £19 during the festive season last year.

The tactics will heap more pressure on high street booksellers such as Waterstone's and Ottakar's, which agreed a takeover this autumn to help them compete against their web-based competitors.