Britain’s Labour government has failed to convince anyone that its decision to deploy over 450 troops and an extra 1,700 police officers at Heathrow airport and parts of London is in response to a genuine security threat from Al Qaeda terrorists.

Security has been stepped up at a number of regional airports, but the focus is on the capital. The extraordinary scenes of tanks guarding airport runways and entrances to Heathrow is only the most extreme example of the security measures being taken. The Ministry of Defence has confirmed that the Royal Air Force have been involved in surveillance operations above London, whilst police officers are mounting stop and search operations at selected London Underground rail stations, demanding people produce identification, and have also stopped cars.

So great is public mistrust of the government’s motives for the security alert that the Conservative and Liberal Democrat opposition combined to demand a statement refuting allegations that it is a “stunt”. Even BBC correspondents have asked government spokesmen whether the aim is to create a climate of fear in order to justify the planned war against Iraq. In parliament the government refused to respond to the opposition’s request.

The government has repeatedly refused to disclose the intelligence on which it has based the operation. When pressed Labour Party chairman John Reid at first claimed that the government was responding to a threat “of the nature that massacred thousands of people in New York.” Later he was forced to withdraw his emotive statement.

Such explanations as have been offered are contradictory. No one has explained how tanks are meant to stop an attack using a handheld mortar or rocket launcher, much less the threat of bio-chemical warfare.

Similar action is also being taken in New York and Washington by the Bush administration as it enters the final stages of its preparations for war. In both countries the measures have been justified with the claim that the end of the Muslim festival of Eid on Saturday, February 15 could be a trigger for terrorist attacks.

Scotland Yard and MI5 claim that there are 40 Islamic extremists in Britain who are linked to Al Qaeda. The provocative linking of all Muslims with possible terrorist activity was reinforced by press coverage of Asians being stopped and searched.

As well as such general political aims of justifying war on the grounds of a terrorist attack, there is another specific dimension to the latest security operation. The end of Eid also coincides with the antiwar protests taking place across the world. The London demonstration is projected to be amongst the largest, with estimates ranging between 500,000 and one million participants. Thousands of coaches have been hired, and trains booked, to transport people from around the country to the capital.

The political implications of this are highly damaging for the government. Earlier this week Prime Minister Tony Blair appeared on television to insist that even if he were the only person in Britain supporting a war against Iraq, he would remain true to his chosen course.

His statement has put the government on a collision course with the vast majority of working people in Britain. For the past months Blair has been touring the world insisting that Britain is the most steadfast ally of the Bush administration and can be relied upon to back war no matter what. Saturday’s protest will demonstrate before the eyes of the world just how isolated Blair’s government really is and the full extent of public hostility to Bush’s war.

Because of this, for several weeks the government had toyed with banning the London demonstration from its final destination point of Hyde Park. In the end it had to back down because such a flagrant attack on democratic rights would only have galvanised opposition.

The latest security operation not only provides opportunities to limit, at the very least, the size of the protest, but also to mount provocations against it. The Metropolitan Police have urged people not to travel to the capital. A number of Underground stations could be closed and roads are sealed off.

One can not exclude the possibility of coaches and other vehicles being stopped and searched and arrests made. A terrorist threat could also be used to cancel the demonstration, even at this late stage. All that would be required is the announcement of a bomb threat.

Whatever happens on the day, the militarisation of civilian life that is accompanying the drive to war against Iraq represents an ongoing danger to democratic rights. Police have already said that troops could be deployed in central London.

There is no call to be alarmist but one must recognise that we are dealing with a desperate government, that is bent on pursuing a war without any political mandate to do so and which has demonstrated repeatedly its contempt for the democratic rights of its own citizens.