The measures will effectively create a ring of steel around Windsor Castle’s St George’s Chapel where the couple will exchange vows.
The May 19 wedding is one of the largest public events policed by the force and in the run-up more police will be seen on patrol in the town, from armed officers to those with dogs and even mounted police on duty.
With the US actress a big draw both to British and American fans, huge crowds are expected, with the processional route of the carriage ride estimated to hold around 100,000 spectators.
If the number of visitors proves to be a safety issue, Thames Valley Police, in consultation with others like Network Rail and British Transport Police, could order trains not to stop at Windsor’s two stations and close off the route to latecomers.
At the start of the year Simon Dudley, leader of the Royal Borough of Windsor and Maidenhead, called on police to clear rough sleepers from the town before the royal wedding.
The force is aware of the homeless campaign #RoyalSleepOver with hundreds pledging on Facebook to spend the night in Windsor on the eve of the wedding.
Officers will not be moving on rough sleepers although they, and possessions like sleeping bags, will be searched like other spectators along the carriage route.
Street furniture to deter attacks will be stepped up in the coming weeks, with an increase in the number of barriers preventing cars or vans being used as weapons – known as hostile vehicle mitigation – and the Automatic Number Plate Recognition system already in use will be enhanced in the town, as will the CCTV.
Almost every Thames Valley Police officer will be on duty that day but that includes police working right across the force’s area.
Harry and Meghan have invited 600 guests to attend their wedding and 200 family and friends will be at an evening reception hosted by the Prince of Wales at Frogmore House.
Thames Valley Police Assistant Chief Constable David Hardcastle, strategic commander for the wedding, said: ‘We are proud to police the Royal Borough of Windsor and Maidenhead.
‘The force has a long history of policing royal events from the annual Windsor Garter Ceremony to state visits and more recently Her Majesty the Queen’s 90th birthday.
‘The wedding of Prince Harry and Ms Markle is no exception. We are working with our partners, local businesses and the community to deliver a safe, secure and happy event for everyone.’