The UK has a number of policies and traditions that reduce this tendency, in addition to snap elections.
Obviously in a sense politicians are always campaigning, in the sense that they're always looking to deliver on their election promises, raise their personal profile, announce popular policies, kiss babies and so on. But that's a constant background effort, rather than an election-specific effort.
Perhaps the most important factor is the campaign spending limit; a campaign might have £50,000 to spend in a constituency with 70,000 voters and when the money runs out, they can't legally spend any more. So any money you spend early is money you can't spend later.
Also a great deal of campaigning involves the candidate physically being in their constituency, not in Westminster. So to start campaigning early would involve a burdensome amount of travel, and much less free time to spend with family.
During the short campaign period, parliament is dissolved and public servants enter 'Purdah' [1] where no important policies can be announced. Candidates can spend all their time in their constituencies campaigning - but the government is basically in stasis.
Obviously in a sense politicians are always campaigning, in the sense that they're always looking to deliver on their election promises, raise their personal profile, announce popular policies, kiss babies and so on. But that's a constant background effort, rather than an election-specific effort.
Perhaps the most important factor is the campaign spending limit; a campaign might have £50,000 to spend in a constituency with 70,000 voters and when the money runs out, they can't legally spend any more. So any money you spend early is money you can't spend later.
Also a great deal of campaigning involves the candidate physically being in their constituency, not in Westminster. So to start campaigning early would involve a burdensome amount of travel, and much less free time to spend with family.
During the short campaign period, parliament is dissolved and public servants enter 'Purdah' [1] where no important policies can be announced. Candidates can spend all their time in their constituencies campaigning - but the government is basically in stasis.
[1] https://en.wikipedia.org/wiki/Purdah_(pre-election_period)