A killer line from Ronald Reagan, then aged 73, in one of the 1984 TV debates with Walter Mondale (56) came when he said that he was not going to exploit for political purposes his opponent's youth and inexperience (HERE).
The joke served him well, but wouldn't work at all in the UK today - where increasing youthfulness and inexperience has been steadily becoming the norm among our leaders since Harold Wilson became Prime Minister at the tender age of 48 - as can be seen from the following two tables.
Table 1: Age and experience of current UK main party leaders
Years as an MP before
Table 2: Age and experience of Prime Ministers since Wilson