Colonel Richard Kemp has told Daybreak that there has been an increase in attacks to British troops in Afghanistan.
He said: "The Taliban know we are getting out in 2014 and their efforts are focused on showing the world and their supporters that they are driving us out."
More top news
Prince Harry is in Toronto, the host city of the Invictus Games, ahead of Saturday night's opening ceremony.
The Prime Minister said she expected an implementation period of "around two years" as she called for a "creative" approach to talks.
The first signs of autumn are appearing as the equinox marks the start of the season.