SP Angel commented in a note following Attenborough's remarks after Nautilus Minerals' (CN:NUS) sub-sea mining plans were outlined on the programme.

Nautilus has been granted an environmental permit and mining lease for its underwater Solwara 1 copper-gold project off Papua New Guinea.

"We agree with Attenborough on the ecological risks of mining active smokers [which Nautilus is not proposing to mine] but we also see huge damage and risk to the seas from bottom trawling nets with heavy machinery," SP Angel said.

It noted DeBeers had been mining and "vacuuming diamonds up off the sea bed for decades" using similar machinery to Nautilus off the coast of Namibia.

"While some also complain about trenches to bury oil pipelines and sub-sea telecoms and power cables but when it comes to mining, the world's most famous and respected commentators are lined up in opposition," the note said.

"We wonder who will line up against Planetary Resources when they start mining their first asteroids?

"Will it be the Green-Space or Asteroids Have Rights Group?"

Nautilus is facing prolonged funding problems and last week said it was in discussions over potential remedies after the shipyard had notified it that the buyer of its production support vessel had defaulted on a contract payment.