Luke Shaw has been ordered to undergo a special training programme after Louis van Gaal raised serious concerns about the Manchester United defender’s fitness in advance of the new season.

Van Gaal struggled to conceal his dismay that Shaw had returned so out of shape for pre-season barely a fortnight after returning from the World Cup finals with England.

Shaw, who became Britain’s most expensive teenage signing when he joined United from Southampton for £28 million last month, arrived home from Brazil on June 25 and then went on holiday before reporting early for duty at United’s Carrington training base on July 10.

The United manager is unhappy at his level of fitness, however, and has had the left back working alone with the club’s