A quarter of NHS Trusts are compounding the risk of hospital infections by failing to meet core standards on hygiene, the UK's healthcare regulator has found.

An ongoing inspection programme by The Care Quality Commission (CQC), which replaced the work of the now disbanded Healthcare Commission and the Commission for Social Care Inspection, found 42 of the 167 trusts inspected last year to be "in breach" of NHS registration requirements.

An alarming catalogue of failures included 36 trusts which the CQC claim had not provided areas for instruments to be cleaned, 3 trusts where staff were "not being suitably trained, informed or supervised" and 11 ambulance trusts that were initially found to have violated the terms of their NHS contract. Overall, the picture we saw at initial inspections in 2009 did raise some areas of concern.

Nigel Ellis, CQC Head of National Inspection, said: "Most ambulance trusts had a significant number of actions to take to raise their performance to the level required. In three cases we took the decision to issue a warning, specifying exactly what was needed and by when. The trusts rose to the challenge – we've seen swift and tangible improvements – on follow-up all were meeting the required standard."

The CQC is set to unveil new powers later this week which will allow it to impose tough sanctions that could see hospitals incur heavy penalties or even shut down if they fail to comply with the regulator's demands.

It came as rules preventing visitors from sitting on a patient's bed or giving flowers were criticised by a leading doctor, who said they were "dehumanising". Writing in the British Medical Journal, Dr Iona Heath said there was "no hard evidence" that either prevented the spread of infections.