Ocado has revealed that orders made on mobile phones have surged to account for over a fifth of its total sales, as it posted a double-digit uplift in first-quarter revenues. The online grocer also forecast an accelerated growth rate, having \"largely\" overcome constraints at its warehouse in Hatfield, Hertfordshire, which led to a profits warning before Christmas. Ocado grew its gross sales by 10.9 per cent to £162.1m for the 12 weeks to 19 February.