"The wedding is expected to attract thousands of people from around the world to Windsor and planning is well under way".
Prince Harry and Meghan Markle are set to tie the knot on May 19 at St. George's Chapel, Windsor Castle.
Those arriving in Windsor by train will be screened and searched in airport style checks.
Police said there would be a steady build-up of security in Windsor in the coming weeks.
British Transport Police will be patrolling railway stations and carriages linking other regions with the town of Windsor.
British pubs will be allowed to stay open late on the eve of the wedding and on May 19, for what the British Government has described as "a day of national celebration".
On the day armed officers will mingle with the crowds while snipers will be deployed on rooftops.
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"A broad range of visible security measures are already in place, such as the extensive network of Automatic Number Plate Recognition (ANPR) technology, Close Circuit Television (CCTV) and Hostile Vehicle Mitigation (HVM) barriers".
Metal barriers will be erected in the Berkshire town to deter attackers from using vehicles, like the terrorist atrocities committed on London and Westminster bridges.
Police and security chiefs have been studying lessons learned from the five terror attacks in London and Manchester previous year, in particular, the atrocities on London and Westminster bridges where vehicles mowed down crowds.
'We are working with our partners, local businesses and the community to deliver a safe, secure and happy event for everyone'. "The military, and these units, in particular, hold a great significance for Prince Harry and the couple are incredibly grateful for their support", the palace's statement read. Symbolism for her love of Prince Harry?
The force assured residents that day-to-day policing and the response to incidents would not be affected by the Royal wedding.
So far there is no intelligence of any specific security threat to the event.
The title has never been used before in an invitation to a royal wedding and is in stark contrast to, for instance, the 2011 wedding invitations for Prince William and the Duchess of Cambridge's wedding, when she was referred to as "Miss Catherine Middleton".
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