Sol Campbell leaving Spurs for Arsenal on a free, Mo Johnston crossing the Old Firm divide and Luis Figo having a PIG'S HEAD thrown at him… here are football's most SHOCKING …

After Paul Ince sensationally claimed Manchester United should attempt to pinch Sergio Aguero from rivals Man City, it got us thinking of the most explosive transfers in football history.

Imagine Aguero representing bitter rivals United, having become City’s all-time top goalscorer after netting an incredible 257 goals in 384 appearances. A move is unfathomable.

Ince even went as far as comparing a possible move to Eric Cantona’s acrimonious transfer from Leeds to bitter rivals United back in 1992.  

So following Ince’s remarkable claims, Sportsmail has decided to take a close look at 10 of the most bitter and controversial transfers in the history of football… 

Paul Ince recently claimed Manchester United should swoop for City striker Sergio Aguero 

MO JOHNSTON (NANTES TO RANGERS – 1989)

In 1989, Jonhston was seeking pastures new after his two-year spell in France with Nantes was coming to an end. Making the return to Celtic appeared the natural move. But almost soon after, all hell broke loose.

The die-hard Celtic fan had become a goalscoring hero at Parkhead between 1984 to 1987 – playing almost 100 games and winning the league title in 1986. He was on the brink of a return to his beloved club, giving a news conference and posing outside the stadium, but the deal soon collapsed.

Just a couple of weeks later, the Scottish striker astonishingly joined arch rivals Rangers – who paid £300,000 more to land him for £1.5million.

The transfer left many raging, not just Celtic fans. Parkhead fans rightly felt betrayed but some Rangers supporters were also far from happy about the move as he was the first high-profile Catholic player to feature for the club.

During Jonhston’s Rangers spell between 1991 to 1993, he scored three goals against Celtic and was struck in the face by a pie from the away end after one of the Old Firm derbies at Ibrox.

Mo Johnston (centre) comes up against his former club Celtic for bitter rivals Rangers in 1989

Rangers manager Graeme Souness poses with his controversial new signing Johnston  

LUIS FIGO (BARCELONA TO REAL MADRID – 2000)

Another incredibly bitter transfer – this time between El Clasico rivals Barcelona and Real Madrid. 

‘As a player at Barcelona, he never hid from anything,’ commented one of Luis Figo’s team-mates after his massively controversial £36.2m move to rivals Madrid in 2000. 

But even Figo was in for a shock when he made the move to Los Blancos, with furious Barcelona supporters more than making their feelings clear when he returned to the Nou Camp for the first time.

On his first return to Barcelona in October 2001 with Barcelona’s arch rivals, oranges, cigarette lighters and bottles were launched onto the pitch whenever the Portuguese star touched the ball. 

Figo smartly stayed away from corners that day as banners with the words ‘Judas’ and ‘Scum’ were dotted around the stadium. Just a year later, a pig’s head was hailed onto the pitch in Figo’s direction. The transfer still lingers like a bad smell to this day.

Barcelona fans were infuriated when Luis Figo decided to join arch rivals Real Madrid in 2000 – and he had a pig’s head thrown at him at the Nou Camp (circled)

SOL CAMPBELL (TOTTENHAM TO ARSENAL – 2001)

Still to this day, Campbell’s shock move from Tottenham to north London rivals Arsenal remains the most controversial transfer in the Premier League. And it all stems from a broken promise, much to the delight of Gunners fans.

During the 2000-01 season with his Spurs contract running out, Campbell declared that he wanted to stay at White Hart Lane and it looked inevitable he would renew his deal.

But after months of ongoing speculation, Campbell stunned English football after turning up with Arsene Wenger at a news conference as Arsenal had announced they had signed the Tottenham centre back on a FREE transfer. No one could quite believe it – the media and fans were none the wiser.

However things turned extremely ugly on his first return to White Hart Lane, with hundreds of ‘Judas’ banners dotted around the ground that day and the animosity has hardly chilled since. 

But what a move it turned out to be for both Arsenal and Campbell. He won two Premier League titles and two FA Cups at Highbury – and is widely viewed as one the Gunners’ best ever centre backs after starring during the Invincibles season in 2003-04.

Sol Campbell’s free transfer to Arsenal from north London rivals Tottenham stunned football

Tottenham fans hold up ‘Judas’ signs on Campbell’s first return to White Hart Lane

ASHLEY COLE (ARSENAL TO CHELSEA – 2006)

This time it was Arsenal fans who let their grievances be known after Cole, who came through the club’s academy, decided to join London rivals Chelsea in 2006 after becoming a household name with the Gunners.

Cole became an integral part of Arsenal’s side but his transfer to Chelsea made headline news. The west London club approached the left back in January 2005 having become disgruntled about his contract situation at Highbury.

The meeting – which took place with Jose Mourinho in a hotel restaurant – was declared an illegal approach, and Cole, Mourinho and Chelsea were all later fined by the Premier League.

But none of this impacted the transfer and Cole made the bitter move to Stamford Bridge in the summer of 2006. Arsenal fans tore into their former left back, who later became known as ‘Cashley’ in north London.

But Cole didn’t look back – going onto win one Premier League and Champions League title, as well as four FA Cups.

Ashley Cole’s transfer to Chelsea still leaves a a bitter taste in the mouth for Arsenal fans

Arsenal fans taunt Cole as they throw fake cash into the air at Stamford Bridge in 2006

CARLOS TEVEZ (MANCHESTER UNITED TO MAN CITY – 2009) 

Another Premier League…