Zinedine Zidane appears to have ruled out any possibility of Manchester United signing Gareth Bale this summer, insisting that the player is simply not for sale to any club.

The Welsh international, who became the most expensive player in football history when he moved to the Santiago Bernabeu from Tottenham for an eye-watering £85m ($124m) fee in September 2013, impressed hugely during his maiden La Liga campaign and also played a pivotal role in Real winning their 10th European Cup.

Bale has not hit quite the same individual heights this season, however, and has attracted strong criticism from a section of supporters and indeed the Spanish press.

He was confronted by angry fans following another indifferent display in the 2-1 defeat to bitter rivals Barcelona in March and displayed his obvious frustration at such unfair treatment during his celebrations following a goal against Levante.

Despite that increasingly fractious relationship and strong links to Manchester United, Zidane, a prominent member of the Galactico era who now coaches Real Madrid Castilla, believes that Bale will not be sold and remains integral to the club's fortunes moving forward.

"Real Madrid buy the best players in the world, they don't sell them. Of course other clubs will be interested in him, he would improve any squad in the world," he was quoted as saying by the Daily Mirror.

"But the president has said he is not for sale – and that is because he is not for sale. That will be the answer to Manchester United or any other club that asks the question.

"He was a big part of our success last season especially in the Champions League, and as we look to defend our title I am sure he will play a successful part again."

Despite sustained disapproval at his performances, Bale has still registered 19 goals and nine assists in all competitions so far this season and, along with Karim Benzema and Cristiano Ronaldo, has received public assurances from manager Carlo Ancelotti that he will not be dropped.

Real are second in La Liga and trail Barcelona by two points having recorded comfortable victories over Granada, Rayo Vallecano and Eibar in recent weeks.

Ancelotti's side are back in Champions League action on 14 April and face a short trip across the capital for the first leg of their quarter-final tie against Diego Simeone's Atletico.

Bale is expected to be fit to feature at the Vicente Calderon having missed Real's last outing with a thigh problem.