Philippe Coutinho has put pen-to-paper on his five-and-a-half-year contract to officially join Barcelona from Liverpool in a deal worth a British transfer record of £142 million.

The 25-year-old completed his medical and finalised his move on Monday before being presented to the Spanish media with a press conference, signing a deal thought to be worth £240,000-a-week.

Coutinho takes the No.14 shirt at Camp Nou - previously held by another former Liverpool player, Javier Mascherano, and will have a buy-out clause inserted into his long-term deal worth an astronomical £355 million.

The Catalan club's lengthy pursuit of the Brazilian finally reached a conclusion on Saturday with the two clubs agreeing a fee that will see the Reds receive around £105 million up-front, with a further £37 million in achievable performance-based add-ons.

It comes after a summer saga saw Barcelona have three bids rejected, while Coutinho submitted a transfer request which was also immediately rejected, but Liverpool have since relented on their stance to reluctantly sanction the move.

Barcelona pushed for a deal to be done in January to allow Coutinho to acclimatise to his new surroundings before he is available for all competitions next season, as well as to avoid a potential hike in the fee were the playmaker to impress at the World Cup in the summer.

Coutinho becomes the second-most expensive signing of all time, behind only compatriot Neymar who completed an earth-shattering £198 million move to Paris Saint-Germain in the summer.

It is the most expensive transfer, incoming or outgoing, ever involving a British club - the previous being Paul Pogba's £89 million move from Juventus to Manchester United.

Coutinho realising "dream" by signing for Spanish giants

The Brazilian becomes Barcelona's most expensive ever recruit and said: "For me it's an honour but I'll leave the topic of money for the clubs. What I want is to play and have success.

"My dream was to come here. I had no doubts about coming here, I have a five year contract and I hope I can play a lot of games in these years. I’ve played in La Liga already and want to adapt as soon as possible with my team-mates."

The midfielder expressed his gratitude towards Barcelona president Josep Maria Bartomeu for facilitating the transfer and the club's directors who "had so much patience."

He also added: "I would like to thank Liverpool for the five years I had there and the directors, Mike Gordon who understood what I wanted, my dream, and they tried very hard to convince me to stay. To the fans who shared five years with me, thank you."

Bartomeu said of the deal: "We knew it was not going to be easy to get him here. We've been talking and working for months on this, but one of the important aspects was he wanted to come here."

He referred to Coutinho helping to "make an effort" to force through the deal - reportedly paying £9 million out of his own pocket towards the deal - and praised his patience which was "key."

"I also want to thank Liverpool, one of Europe's biggest clubs, for allowing him to leave and come here," he concluded.

Thigh injury to delay Coutinho's debut

The playmaker will be cup-tied for the UEFA Champions League, having played in the competition for Liverpool this season, but will help to ease the burden on Iniesta.

Coutinho will have to wait for his debut, however, with a thigh injury set to keep him out for three weeks - meaning he could make his debut in the derby against Espanyol, where he spent a season on loan under Mauricio Pochettino in 2011-12.

Once fit, Coutinho will play an important part in La Liga, with Barcelona unbeaten and nine points clear of second-placed Atletico Madrid. They boast an almost-insurmountable 16-point advantage over rivals and reigning champions Real Madrid.

He is expected to start the majority of their domestic games in order to allow Iniesta to remain fresh for European challenges. They face Chelsea in the last 16 of the Champions League next month.

Coutinho - who joined Liverpool five years ago from Inter Milan for just £8.5 million - leaves having scored 54 goals in 202 appearances, with 41 goals and 35 assists coming in 152 Premier League matches.

Coutinho's departure is believed to have been sanctioned by manager Jürgen Klopp, though the player had contributed 12 goals and nine assists in just 20 appearances this season.

The German values commitment and a strong squad camarederie above all, and so gave the green light for Coutinho to leave despite his obvious quality and importance to the Merseyside outfit's team.

His loss leaves a huge void in the Liverpool squad, although it is unlikely that they will sign any replacements this month - with AS Monaco's Thomas Lemar a potential summer arrival having been a long-time target. They are also unlikely to convince RB Leipzig to allow them to sign Naby Keïta early even despite an increased offer.