Geoffrey Boycott has branded Australia "so bad it's unbelievable" and reckons a second-string England side would beat them.

Alastair Cook's men skittled the Baggy Green for 60 at Trent Bridge on Thursday and, after another stellar day, return on Saturday needing three wickets to regain the Ashes.

Few predicted that before the series - Boycott included - but the former England opener has been left stunned by Australia's batting.

"I cannot believe that before this series started I picked Australia to win 2-1," he wrote in the Telegraph.

"If I had seen how badly Australia bat against the moving ball I would have been running to the bookies to put money on England.

"They are so bad it is unbelievable. They do not learn."

The fifth Test at the Oval is likely to be a dead rubber if England, as expected, take a 3-1 series lead.

Although such a move would be unprecedented, Boycott believes England could pick a weakened side and still win in London.

"The last laugh is on them (Australia)," he added. "They have been so poor in batting that maybe we should play four or five of our second-teamers at the Oval so we can give them some experience and see how they go against this second-class Australian team.

"Obviously England will not do that, but this lot are so bad I think we would still win if they did."

The Yorkshireman also branded Steve Smith - the world's number one batsman - as "pathetic".

Short of a double hundred at Lord's, Smith has struggled to impose himself fully and has scored just 11 in this Test, twice being removed by Stuart Broad.

"Australia's most prolific batsman over the last 12 months, Steve Smith, has played like a novice," Boycott said.

"He is a flat-track bully on easy batting pitches but in six innings on the three Test-match pitches where the ball has moved laterally he has had a bad technique and he has shown poor shot selection and an inability to graft or work for runs. In those six innings he has scored 92 runs. Pathetic."