Manchester United tipped to buy Liverpool's Joe Allen - could it really happen?

Liverpool and Wales midfielder Joe Allen is reportedly in line for a move to Manchester United, according to the South Wales Evening Post.

"Allen's future at Liverpool is still uncertain with just 12 months remaining on his contract and talks over an extension yet to begin," the story reads, adding that Swansea had been expected to land the 26-year-old.

"But United, who are reshaping their midfield under Mourinho - the futures of Bastian Schweinsteiger, Ander Herrera, Juan Mata and Marouanne Fellaini are all unclear - could offer Allen European football if their bid is firmed up."

Almost certainly not. The enmity between the two clubs is such that they simply do not transfer players directly between them.

It has happened in the past - though the last time was 52 years ago, when a player called Phil Chisnall moved from Liverpool to United in 1964.

Since then, however, no player has moved directly between the two clubs. It has become football's great transfer taboo.

Among giant clubs on the European stage, yes. Real Madrid and Barcelona have no such compunction about doing business, nor do Bayern Munich and Borussia Dortmund, nor either of the Milan giants.

The only equivalent in football exists between Celtic and Rangers, who have had no direct transfers between them since the Second World War. (Interestingly, there were quite a few before then)

Gabriel Heinze almost broke the taboo by joining Liverpool nine years ago, but United literally called in their lawyers to find a way to block the deal - despite the player having a seemingly-clear exit clause that the Reds had matched.

Then, last year, Raheem Sterling was widely tipped to be swapping Liverpool for Manchester United; in the end, Sterling moved to Manchester City instead.

Considering that he struggled for time on the pitch during Liverpool's campaign last season, and considering that Paul Pogba and several other big names are expected to arrive at Old Trafford this summer, it seems unlikely. That said, Allen was brilliant at Euro 2016 - earning a spot in the UEFA team of the tournament - and the resultant boost in his confidence means he could be ready to move his career up a gear.