Afridi had a disappointing debut as Test captain at Lord's
Pakistan captain Shahid Afridi is to quit Test cricket after the second game of their series against Australia.
The 30-year-old only confirmed his return to Tests after a four-year absence in May when he was named skipper for the tour to England.
But he announced his decision to step down following Pakistan's 150-run loss to Australia at Lord's on Friday.
"I would rather focus on one-day and Twenty20 cricket," all-rounder Afridi told BBC Test Match Special.
"It is a board decision, but I would think Salman Butt is the best man for the [captaincy] job now."
The 'home series' against Australia is taking place in England because of ongoing concerns about the security of touring teams in Pakistan.
The Pakistan Cricket Board will have to move quickly to appoint a successor as the second Test against Australia starts at Headingley next Wednesday and it is followed immediately by a four-match series against England.
"I did the wrong thing. I think my temperament is not good enough for Test cricket and I am struggling with my side as well," he said.
"In Test cricket the demands are totally different. You can say I am not strong enough mentally. Captains should be an example for youngsters and for the team but I didn't show any example. I am not capable of playing Test cricket."
Afridi was given the captaincy in the wake of Pakistan's dismal tour to Australia last winter where they lost every international fixture.
The PCB subsequently gave indefinite bans to former skipper Younus Khan and Mohammad Yousuf because of dressing-room disharmony and although the bans were subsequently lifted, Yousuf decided to retire and Younus was not selected for the current tour.
The decision to exclude Younus was a mistake, according to Afridi.
"We need experienced players in these English conditions. We need Younus Khan," he commented.
Despite being one of one of the most aggressive and exciting one-day batsmen in world cricket, Afridi has struggled to adapt his approach to the five-day game.
He has made five Test centuries during his career, but gave his wicket away with a rash shot in each innings at Lord's, where he made scores of 31 and two.
"He feels he doesn't fit into this and for the best interests of the team he will step down," coach Waqar Younis commented.
"It's hard to pressure him [to carry on]. He feels it's just not right for him at the moment. He believes in himself but it was just not a match for him here."
Although Afridi intends to miss the Tests against England, he is likely to return for the Twenty20 and one-day games which follow.
And Waqar said he could retain the captaincy for those formats of the game.
International Cricket Council chief executive Haroon Lorgat, meanwhile, said it was likely Pakistan would have to continue playing at neutral venues for the "foreseeable future".
But he told Test Match Special that there were "still issues to be resolved" at government level before Pakistan could play a series against India at English grounds.
Highlights - Afridi stars in Twenty20 win over South Africa in 2009 (UK only)