The Royal Navy could lose its ability to assault enemy held beaches, under plans being considered in the Ministry of Defence, BBC Newsnight understands.
Two specialist landing ships - HMS Albion and Bulwark - would be taken out of service under the proposals.
The plan - part of a package of cost-cutting measures - has caused alarm among senior Royal Marine officers.
The MoD told the BBC that no decisions have been made yet and that discussion of options was "pure speculation".
It is understood the head of the Royal Navy, Admiral Sir Philip Jones, formulated the move as part of a package designed to balance the books and free up sailors for the service's two new aircraft carriers.
Critics say the proposal would deprive the Royal Marines of its core mission.
Among other cuts envisaged are a reduction of 1,000 to the strength of the Royal Marines and the early retirement of two mine-hunting vessels and one survey vessel.
A senior Royal Marine officer blamed the introduction of the new carriers for exacerbating the senior service's financial and manning problems.
He told the BBC: "This is the worst procurement decision of the past half century - that's what the Royal Marines are being sacrificed for." (end of excerpt)
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