Image caption A post box in Southampton city centre was painted blue

People have been left stumped as post boxes have been painted blue in various towns and cities across England.

The paint jobs, spotted in the centres of Southampton, Leeds, Nottingham and Taunton, sparked speculation among locals.

But after some noticed the locations were all due to host matches in the forthcoming Cricket World Cup, it wasn't long until the secret was out.

An International Cricket Council spokesman (ICC) confirmed the link.

Painters in Southampton left behind a conclusive clue, in the shape of an unbranded notice taped to the side, stating: "This box has been painted blue to celebrate the 2019 Cricket World Cup."

The box was spotted in Above Bar, in the city centre.

Image caption A sign on the side of the Southampton post box gave the game away

Another box appeared in Angel Row in the centre of Nottingham.

An ICC spokesman stepped up to the wicket to confirm: "This is a joint activation between the Cricket World Cup 2019 and Royal Mail which will be officially launched next week."

Post boxes were painted gold in the home locations of gold medal winners in the 2012 London Olympics.

Blue post boxes are not an entirely new phenomenon - they were introduced for air mail letters in the 1930s. Examples remain at Castlefield, Manchester and outside Windsor Castle.

Royal Mail declined to comment on the blue boxes.