I would think its a given that security will be a little more stringent given the current climate. The facts are, security and ant - terrorist organisations in the UK have been doing an excellent job of identifying and preventing potential attacks via deep routed intelligence cells (there have been seven foiled this year).
Granted, they are not 100% sure of preventing every conceivable plot, but chances are, they will hopefully be doing a more thorough job than the French and Belgium's who have a particular problem with radicalisation.
ISIS are undoubtedly creating an atmosphere of fear, but we have to carry on living our lives as normally as possible, otherwise the bastards have won that little propaganda scenario.
We as a country are not part of the Schengen agreement allowing free passage without document checks, and we also live on an Island. The biggest threat to enabling entry by potential terrorists into the UK is via the chaos at Calais and the Tunnel. That will get a real dose of beefing up of security again I guess.
The City of London will be the main target, and that has a ring of steel of security, with more armed cops and undoubtedly other armed forces able to react instantly as they did in Paris on Friday night.
The other major Cities, including Manchester do not have that level of capability as yet I would guess, which is my worry, we run out of cops every day in Manchester to go to normal incidents, let alone multi coordinated attacks. So, expect large gatherings and events to be policed more and security beefed up.
And don't forget, we, as members of the public must have our eyes and ears pealed, and report any suspicious activity to the authorities.