Press have no special privileges of access in UK, their entitlement to photograph is identical to every other citizen. The National Press Card serves only as a means of identification as a member of the press.  Whether it is accepted as such by police is variable.

In some circumstances press cards do achieve greater access, but this is dependent on the operational priorities (or whim) of the police. Press may be admitted to an area that has been closed to the public because of an incident or for security reasons. At other times press will receive extra attention to prevent them photographing even when surrounded by a sea of amateurs clicking away with digicams and mobile phone cameras.