BELEK - Britain will boost its intelligence agency staff by 15 percent and more than double spending on aviation security to defend against Islamist militants plotting attacks from Syria, Prime Minister David Cameron said on Monday.Britain said it had decided to bolster its defenses in the wake of the growing number of plots against Britain and recent attacks, including those in Paris and Tunisia, with Cameron saying Britain had foiled seven potential attacks in the last six months."We have been aware of these cells operating in Syria that are radicalizing people in our own countries, potentially sending people back to carry out attacks," Cameron told BBC radio from the Turkish resort of Belek."Our security and intelligence services have stopped something like seven attacks in the last six months albeit attacks planned on a smaller scale. That's one of the reasons we are strengthening the security and intelligence services."He said Britain faced a generational struggle which required more manpower to counter.The government said that as part of a broader five-year defense and security review, due to be published on Nov. 23, it would fund an extra 1,900 officers at its MI5 and MI6 spy agencies and GCHQ eavesdropping agency.