THE full extent of the attack in London, as well as possible explanations and appropriate responses, will take time to emerge. But the incident close to Parliament is a reminder of several aspects of modern life we might sometimes take for granted: the effectiveness of the emergency services who have been recently planning for an incident of this kind, the personal bravery of those who serve in them, the value and importance of democracy and, of course, the serious threats that exist against it.

It is not a modern threat, or, sadly, an unusual one. In 1979, the MP Airey Neave was killed by a car bomb as he left the House of Commons car park. On July 7, 2005, London also came under a series of attacks in which 51 people were killed and other European countries have faced their own terrors - 77 young people were killed in Norway by Anders Breivik in 2011 and 130 were killed in the terrible Paris attacks of 2015.

There is naturally a temptation to rush to reaction – in the aftermath of the Paris attacks, President Francoise Hollande said his country was at war – but regular and serious terrorist attacks have become an inevitable part of modern life, as are the compromises we have to make to remain as safe as possible. Westminster is much more secure than it was 30 years ago; Holyrood has also spent more money in improving its security. These are the compromises that often have to be made – it was also entirely appropriate for Holyrood to suspend its debate on the independence referendum.

The task now, as ever, is to strike the right balance between improving security and protecting everyday freedoms. We cannot shut down the centre of our cities; we also cannot unduly curtail freedom of movement which is why the restrictions on laptops on certain flights from Middle East countries is troubling. The London attacker may have had a record, or he may have been a “clean skin” unknown to the authorities. Whatever his status, the aim in the next few weeks is to learn as much as possible from the attack and apply the lessons as best we can when, as it inevitably will, terror strikes again.