Does the crime of Treason still exist?

The Treason Act 1351 has since been amended several times, and currently provides for four categories of treasonable offences, one of which is
"if a man do levy war against our lord the King in his realm, or be adherent to the King’s enemies in his realm, giving to them aid and comfort in the realm, or elsewhere".
The duty of the Crown towards its subjects is to govern and protect. The reciprocal duty of the subject towards the Crown is that of allegiance. Allegiance is owed both to the Sovereign as a person and, perhaps more importantly these days,  to the Sovereign in the political capacity.
The definition of treason depends on this allegiance and all British Nationals owe allegiance to the Queen  wherever they may be, which includes those who hold a British passport however obtained. The law also includes aliens (excepting diplomats) present in the United Kingdom at the time of the treasonable act.
Although the law is very complex, the above statements seem quite clear; anyone who endeavours to overthrow the government by force or give aid and comfort to the enemies of the Queen is committing treason.

I have been reading what the media has said about Anjem Choudary and his proposed demonstration at Wootton Basset and also about the Seven Muslim protesters who screamed insults at soldiers on parade at Luton. Her Majesty's Forces are servants of the Crown in both a personal and political capacity, and any insults or demonstrations against them are also demonstrations against the Crown, which in the past has been considered to be treason. If there is any doubt about this, in Choudary's case, he has been preaching the overthrow of British Law and its replacement by Sharia Law. He also is giving aid and comfort to the Queen's enemies in many of his statements and actions. These actions are both clearly contrary to the Treason Act.

So why haven't there been any prosecutions? Has the Attorney General got cold feet or is he too busy arguing against the Tory case for changing the self-defence laws? Or does the government think it would harm racial relations? The latter argument, I believe is fallacious; it is claimed that a majority of Muslims are opposed to the extremists, firm action by our government would convince them and the white majority, that these people are not going to be allowed to interfere with our way of life.

When aliens get UK citizenship they should be made to understand that part and parcel of this is allegiance to the Crown, not just the ability to go and collect the Job Seeker's Allowance and other benefits. Most apparently don't realize this and its about time they learnt, and the best way for them to learn would be a few prosecutions for treason. Anjem Choudary would be a good starting place.