Road closures during Changing of the Guard will take place for an initial three-month trial periodCredit:Philip Toscano/PA From Wednesday, Constitution Hill, the Queen Victoria Memorial, Spur Road, Link Road and The Mall – up to the junction with Marlborough Road – will be closed between 10.45am and 12.30pm on the days of Changing the Guard.Additional barriers will also be in place to maintain security for the guard movements, Scotland Yard said. Armed police outside Buckingham Palace on Wednesday amid heightened securityCredit:Ben Cawthra/LNP Armed officers survey the area as crowds look on outside Buckingham PalaceCredit:Jeff Gilbert for The Telegraph The road closures will take place for an initial three-month trial period, which the Metropolitan Police said had been planned for some time as part of “ongoing security measures”.But the force confirmed that the trial had been brought forward to Wednesday as a direct response to events in Berlin. Standing by were mounted officers, along with several police cars and bicycles, stationed at various points in the cordoned-off area. Buckingham Palace is being protected by a security cordon designed to prevent Berlin-style lorry attacks during the daily Changing of the Guard ceremony.Scotland Yard announced that, starting on Wednesday, roads around the Palace will be closed to traffic between 10.45am and 12.30pm on days when the ceremony is taking place.It attracts thousands of tourists to the Palace every morning and remains one of London’s most popular attractions. Met Commander Simon Bray, responsible for security, said: “The threat to the UK from international terrorism remains severe, meaning an attack is highly likely.”He added: “The Met undertakes a range of different activities including strengthening security and high-visibility policing as part of a counter-terrorist strategy, and it will continue to take whatever action it believes is necessary to protect and reassure the public.”Police continue to work in partnership to minimise disruption, but its priority is to ensure the safety and security of those who live, work and visit London.” An armed police officer outside the gates of Buckingham PalaceCredit:Jeff Gilbert for The Telegraph The announcement came after patrols were on Tuesday stepped up at UK festive markets.Greater Manchester Police said it had strengthened its presence at the city’s Christmas markets, which have almost 350 stalls spread across 10 sites. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Meanwhile, Foreign Office travel advice will describe the terror threat in countries abroad in more detail to help travellers make “informed decisions” about their plans, Boris Johnson announced.It will report on whether attacks are likely to happen, the targets of previous attacks and methods used, which groups are responsible, and what host countries are doing to counter the threat. The changes will be implemented in the coming months.The threat to the UK from international terrorism remains severe, meaning an attack is highly likely. West Midlands Police said it was reviewing security measures and increasing visible patrols in Birmingham, and had a dedicated team of response officers ensuring the safety of visitors to the city’s popular Christmas German market.Visitors to the Southbank Winter Festival, next to London’s Royal Festival Hall, were handed cards warning them about the risk of terrorism as police officers chatted to shoppers. Police outside Manchester Christmas market on Tuesday after the Berlin attackCredit: Jon Super for The Telegraph The lockdown did little to dissuade tourists, who still filled the pavements in their hundreds to witness the celebrated spectacle on Wednesday morning.At 11.30am, the guard began marching from Wellington Barracks and through the Palace gates as a sea of tourist cameras tracked their progress.