England's director of cricket Andrew Strauss has admitted that Alastair Cook gave up his captaincy after becoming "drained" by the role.

The 32-year-old announced this morning that he had stepped down as Test captain with immediate effect after a record 59 matches in charge.

The decision brought to an end much speculation over Cook's future following England's 4-0 series Test defeat in India at the end of last year.

"He was getting drained by the relentlessness of being England captain," Strauss told BBC Sport. "We know it has been a tough winter and it was an obvious time for him to step back and reflect and consider and have thoughts about what was right for the team moving forwards.

"In my conversations with him in January it became clear that Alastair felt a huge amount of energy, drive and determination was needed to drive the team forward over the next 12 months.

"You are the only one who knows how much gas you have left in the tank and how much the many demands of being England captain are taking out of you. He feels it is time for new blood, new impetus and fresh thinking and allow someone else to take over and do that.

"Once it became obvious how clear his thinking was, it was his decision to make. It would have been wrong to persuade him otherwise."

Vice-captain Joe Root is the strong favourite to replace Cook at the helm of the Test side.