By Jeremy McDermott
BBC News, Medellin
Officials say Farc desertions are increasing
The Colombian government says that the country's largest rebel group, the Farc has gone into irreversible decline, hit by desertions and the killings of high-profile members.
Speaking to a Colombian newspaper earlier this week, Defence Minister Juan Manuel Santos said the tough US-backed policy of President Alvaro Uribe was yielding results.
According to the government, the number of rebel fighters is down from 16,000 in 2001 to a current figure of 6,000-8,000.
"They are in a process of splitting; they have lost important leaders... They are facing a shortage of supplies, lack of communications, loss of command and control," Mr Santos said.
The Revolutionary Armed Forces of Colombia has been fighting the Colombian state for five decades.
Three important Farc leaders were killed last year, and their deaths have shaken the Farc, resulting in a loss of morale, according to Mr Santos.
However, the effect of these killings has been felt in specific units, rather than throughout the Farc.
No members of the Farc's ruling body, the seven-man Secretariat, have ever been killed or captured and they continue to run the operations of the Farc's seven divisions or blocs.
Farc leader Manuel Marulanda appears undeterred
Still, in the past two years, desertion has become a real worry for the Farc.
The government has been stepping up an advertising drive to persuade disaffected rebels to desert.
Not only are they losing valuable fighters, but each deserter is being thoroughly debriefed by the Israeli-trained Colombian military, resulting in a gold mine of intelligence for the security forces.
Added to this, the Farc know that their radio and satellite communications are being intercepted thanks to US technology.
The guerrillas have been forced to return to an old, proven method: human couriers.
This means that messages can take weeks to arrive, weakening the grip of the leaders on the more remote fronts, and making large-scale co-ordinated attacks very difficult.
Farc leaders, however, appear undeterred. A communique published on 3 January and signed by the group's legendary founder, Manuel Marulanda, said that 2008 would be a busy year.
Several years of fighting a military offensive had given the rebels the chance "to learn about the enemy and the way that it deploys, and operations, day and night, with its reconnaissance aircraft, bombers, helicopters and satellites", the statement said.
And in one particular area, the Farc is still very secure: its finances.
Despite unprecedented eradication campaigns to uproot coca plants, Colombia still produces some 600 tonnes of cocaine a year.
The Farc's share of the trade ensures that they are still awash in funds, which may allow them to buy sophisticated weapons and replenish their ranks.
And few independent analysts place the number of rebels as low as the government figure of 6,000.
However, many agree on what was regarded as impossible less than seven years ago: that the Farc can be defeated militarily.
"The Farc are in irreversible decline," says Bogota-based security analyst Roman Ortiz.
"They will never recover the strength they once had."
Nevertheless, there are a number of factors which could prolong the conflict.
One unknown is relations with neighbouring Venezuela.
Last year, Venezuelan President Hugo Chavez became involved in mediation efforts to secure the release of rebel-held hostages in Colombia.
But Mr Uribe ended his role in November, saying Mr Chavez had spoken to Colombia's army chief despite being told not to do so.
Awash with petro-dollars, Mr Chavez would have the means to significantly boost the Farc's military capacity should he wish.
Mr Chavez insists he is neutral in the conflict, although he is not unsympathetic to the Farc.
In January, he said the Farc and the ELN guerrilla movement should been seen as insurgent forces not terrorist groups, which is how the Colombian government, as well as the US and the EU, designate them.
Farc rebels have been fighting the government for decades
The jailing in the US on 28 January of Ricardo Palmera, known as Simon Trinidad, further complicates the panorama for the guerrillas and the chances for peace talks.
The most senior Farc commander ever captured, he was sentenced to 60 years in connection with the kidnapping of three US intelligence operatives after their spy plane crash-landed in rebel territory in 2003.
With more than 50 Farc leaders with US extradition warrants pending and facing the threat of long prison sentences, guerrillas might think twice before surrendering.
If the choice is between dying in combat and rotting away in a US prison cell, many guerrillas might choose to fight to the bitter end.
Ordinary Colombians are not convinced the battle can be won any time soon.
While President Uribe enjoys high approval ratings, many believe that a negotiated solution is the only way to end 44 years of civil conflict.
The Farc "may be hard hit militarily and they may fragment, but they will simply turn into the powerful and heavily armed drug cartel in the world" says Juan Gonzalez, a lawyer in Medellin.
"The violence will not end until a peace agreement is signed."