We can’t afford to shy away from hard questions about our security

SIR – Keeping calm – which the Prime Minister and Home Secretary have urged us to do following Wednesday’s terrorist attack in Westminster – should not be the same as complacency. That, however, seems to be the problem at the moment.

The terrorist crashed his vehicle into the Palace Yard fence some considerable way from the gate by which he was able to enter the parliamentary estate. The noise of the crash should have itself been enough to alarm the police and prompt them to firm up an armed presence at the key Carriage Gate entrance.

We need explanations and assurances about what is now happening. Rev Andrew McLuskey Staines-upon-Thames, Middlesex

SIR – It has been reported that Khalid Masood, the perpetrator of the attack, had been known to MI5.

Yet our security services were reactive on Wednesday. They were, of course, brave in the face of adversity. However, only a proactive approach will defeat the terrorists. As for those who wish to murder innocent people, our security services should be given greater powers to deal with them – before they are able to attack. Gordon Scott Dunstable, Bedfordshire

SIR – I am angered by the attempts to find someone to blame for Wednesday’s attack.

Not even 24 hours had passed since the incident when the BBC’s Laura Kuenssberg was intimating that there had been failings by someone in Government, the police or security services. Yet this was a “lone wolf ” attack, which most experts regard as virtually unpreventable.

Of course the authorities and Government are examining the circumstances and determining what might be done to prevent other attacks, but would we want their plans published, or for them to rush to hasty judgment? Of course not; there must be a measured, considered and probably confidential response.

The Islamic State of Iraq and Levant must be delighted by the suggestion that there were faults. It is time to stop the negativity, look for positives – and praise the police and security services. S P Vere London SW19

SIR – The perpetrator of the London attack had a criminal history. To me this came as no surprise at all.

Until my retirement I worked as a probation officer and came across numerous young men (they were usually men) with nothing going for them: no job, little education, prone to violence, poor family ties, few scruples, relationship problems, alcohol, drugs – the list is endless.

Most important of all, they had little inclination to do much about it. In fact, most were waiting for something to happen to them – which is where Isil comes in, catching them at their lowest ebb. Religion itself is irrelevant. Anne Murphy Durham