The Home Secretary has urged NHS trusts to urgently upgrade their computer systems as the health service continues to struggle with the fall-out from Friday’s massive cyber attack.

Amber Rudd’s call came amid a growing row over whether NHS managers had failed to heed repeated warnings about out-of-date computer systems being vulnerable to such attacks.

Less than six months ago it was reported that nearly all NHS trusts were using an obsolete version of Windows that Microsoft had stopped providing security updates for in April 2014.

This left them vulnerable to the sort of attack which on Friday crippled the system of 45 hospitals and clinics.