Does it really make sense now to semi-privatise this public service?

David Winnick

But the government's sizeable majority meant that they were able to see-off the rebellion.

Before the debate in the chamber even began there was a row over the absence of Deputy Prime Minister John Prescott.

Mr Prescott, head of the transport, environment and regions super-ministry, was accused of ducking the debate by shadow transport minister Bernard Jenkin.

He said Mr Prescott had "ducked the debate on the fuel crisis, he ducked the debate on the London Underground PPP [Public-Private Partnership] and now, as I predicted, he is ducking this.

Controllers' unions fear the part-privatisation plans will jeopardise safety

"It is getting beyond a joke."

Early in the debate former Labour transport minister Gavin Strang, a fierce opponent of the sell-off, was one of the first backbenchers to rise and voice his opposition to the government's plans saying they were entirely about "financial considerations".

He also said that privatising the service that also controlled the UK's military aircraft would have implications for national security.

Safety 'paramount'

Environment Minister Nick Raynsford insisted that safety would be paramount in a partially privatised Nats.

He called on MPs to vote down the Lords amendment.

He said: "Were this provision to remain on the face of the bill, we would be straying into very dangerous territory in constitutional terms, and creating a precedent which could be used again and again to damage the good intentions of this government."

But a core of Labour MPs, including Mr Strang and former Heathrow Airport shop steward Martin Salter, were determined to defeat a move which they say did not even feature in the party's general election manifesto.

Martin Salter: Privatisation proposals "ill-thought-out"

Labour MP for Walsall North, David Winnick, drew the comparison between Tory privatisation of the railways and the privatisation of Nats.

"At a time when we are seeing in practice what has happened on the railways as a result of Tory privatisation, does it really make sense now to semi-privatise this public service. Surely this is not the time to do so?" he asked.

Mr Raynsford insisted the government's plans were "very different" from what had happened to the railways.

Under the government proposals, 49% of the air-traffic service would remain in public hands with 5% going to employees.

Ministers will also retain a so-called "golden share", meaning a complete sell-off in the future could not go ahead without government approval.

Bid to 'neutralise' rebels

Before the debate, Mr Salter said government whips had been working overtime to neutralise potential troublemakers.

As a result, there were fewer rebels than the last time MPs voted on the issue in July, when 47 Labour members defied the government.

The MP claims 76% of the public oppose the sell-off of Nats, making it less popular than fox hunting.

Prime Minister Tony Blair's official spokesman has said, however, that the government remained "absolutely committed" to the part privatisation.

"There is a huge increase in air traffic and this, we believe, is the best way of getting the necessary investment in.

Later, a further vote over the issue of the Nats pension fund was also won by the government with a majority of 134.

That vote was also sparked by a Lords amendment which said that the pension fund should be afforded "statutory protection" in the event of NATS passing into the private sector.

But for the government, Mr Raynsford said such protection was "not needed" because staff's pensions would be protected enough under Government plans.