Paul Lambert's admission on Ipswich allowing Matt Clarke join Portsmouth for cut-price deal

And the Portman Road boss also pinpointed the Tractor Boys were undercut when selling ex-Blues defender Adam Webster.

Clarke made his move to Fratton Park permanent in 2016, having spent the previous campaign on loan.

He was a makeweight for Webster heading the opposite direction.

Clarke went on to make hurtling progress on the south coast – twice being named The News/ Sports Mail Player of the Season – before being sold to Premier League Brighton in the summer for a fee of around £4m.

Webster too sealed a switch to the Seagulls from Bristol City for a reported £20m just a year after departing Ipswich for £3.5m.

Lambert knows his club have been stung before he took the reins in October 2018.

And with centre-back Luke Woolfenden being linked with Sheffield United during this month's transfer window, the Scot won't allow the same mistake to happen again under his watch.

Lambert told the East Anglian Daily Times: ‘The way the modern game is? Absolutely, absolutely (Woolfenden is worth £10m).

‘Potentially what he could be, 100 per cent he is. The level of money and the way the game's going, I see players move for money they shouldn't be anywhere near.

'But Woolfy is in the category of what you can buy now and what he will be like down the line.

‘I know the level of the Premier League and the Championship and there's no way you can allow people to leave here like Webster and Clarke did.

‘If somebody came in with £20m or whatever it is that's one thing you can't ever stop. We're not in a position to turn down that kind of money. It's impossible.

‘If that happens it happens but hopefully it doesn't because he's playing really well.’

Elsewhere, Pompey have been linked with a move for ex-Ipswich centre-back Tommy Smith.