What does the next 12 months have in store for the British military? (Picture: MOD).
The UK's leading independent think tank on international defence and security issues believes the aftermath of Brexit will have a major impact on the future shape of Britain's armed forces.
Deputy Director-General of the Royal United Services Institute, Professor Malcolm Chalmers, says the government will probably launch a spending review, which could affect defence spending.
An additional £1 billion in funding was confirmed in the Budget in October.
Professor Malcolm Chalmers added spending was still an area of uncertainty:
"It feels as if we're not going to have big cuts in defence but nor are we going to have big increases."
Professor Malcolm Chalmers gives his predictions for 2019 in defence.
Professor Chalmers warned the shadow of Brexit could also open the door to another national vote, which could offer an opportunity for Russian intervention.
"We've seen that happen in France. In the United States. Arguably in our last Brexit referendum. We can't afford for that to happen again."
He was speaking before a letter was sent to the chairs of Conservative Party associations urging MPs to reject Theresa May's Brexit withdrawal deal on grounds of national security was publicly released.
Also, Professor Chalmers warned that the issue of Russian intervention would be a very important priority. He said:
"Russia is going to take opportunities when there are low cost ways of interfering with our democratic politics in Europe."
Professor Chalmers also said there is likely to be political pressure on the Royal Navy to deploy its two new aircraft carriers when they come into service.
He said: "Once we have two aircraft carriers up and running, to actually have them seen around the world being used in terms of presence, in the Indian Ocean, South China Sea, you name it, there will be an expectation of having our carriers with many of their escorts out there doing their thing."
"That puts enormous stress on our services - we're not going to have the UK carrier going up against the Chinese in ten years time by ourselves."
Queen Elizabeth left Britain in August to begin flight trials in the United States, allowing two F-35B fighter jets to conduct 500 take-offs and landings.
In total, the aircraft carrier cost £3bn to build and the Ministry of Defence spent £190 million on each F-35.
At full capacity the warship will be able to carry 72 F-35 jets.
Britain's military deployments in Syria and Afghanistan are also likely to change according to Mr Chalmers.
He said US President Donald Trump's commitment to withdrawing his forces from the countries will see Britain follow suit.
“Both in Syria and Afghanistan it’s hard to conceive of the UK continuing to put its forces at risk on the ground unless they have cover from the Americans.”
He went on to say:
"We arrived with the Americans and I think we would depart with the Americans also."