It should be noted that a trademark registration takes longer if a trademark is refused or if an older trademark objects and opts for opposition.
If you want to register in several countries worldwide, international registration is easily the most advantageous depending on the type and number of countries. If you only want to register your trademark in the UK, this is done via the national registration. The costs are relatively low and the chance of objection is relatively low as well.
From 2020, an EU trademark application is not an option anymore if you need protection in the UK due to Brexit.