Concluding his summer drinking round-up, JONATHAN RAY picks a host of wines suitable for the great British summer. For picnics, he suggests the 'light and frothy' 2004 Brown Brothers Moscato (5.99; Tesco); for barbecues, he opts for 2003 The Boulders Viognier (4.99; Co-op), which 'has no shortage of spicy, aromatic flavour'; while for weekday suppers he plumps for the 'charming, light and elegant' NV Prosecco (6.99; Marks & Spencer).