British jihadists fighting in Syria and Iraq should be charged with treason for giving "aid and comfort to the Queen's enemies", MPs have heard.

Conservative backbencher Philip Hollobone insisted the British public wants to see "exemplary" prosecutions for treason as the Islamic State, also known as Isis, and other extremist groups are "sworn enemies" of the UK.

But Justice Minister Simon Hughes told the Commons that the Government needs to ensure it has extensive powers to prosecute people who commit serious offences abroad or when they return to the country, adding plenty of powers exist without using treason laws.

The last treason prosecution emerged in 1945, the Liberal Democrat frontbencher told MPs.

Prime Minister David Cameron has previously said the intelligence and security services believe that at least 500 Britons had gone to fight in Syria and potentially Iraq.

Speaking during departmental question time, Kettering Tory Mr Hollobone told Mr Hughes: "Isis, al-Qaeda and other groups are sworn enemies of our country and hate everything we stand for and British citizens who go abroad to take part in jihad or holy war are giving aid and comfort to the Queen's enemies.

"The British public want to see some exemplary prosecutions for treason so that the seriousness of this international terrorist activity can be fully and properly recognised."

Mr Hughes replied: "I hear what you say and all ministers in all departments are very clear that we both need to use effectively the powers we already have and that we have to take new powers, which have been announced by the Prime Minister, to fill any potential gaps in the protections we have.

"They will be targeted, they will be proportionate, they will be effective and they will ensure our commitment to international law and human rights.

"But as a Liberal Democrat minister can I make it absolutely clear on behalf of all of our team in the Ministry of Justice, that we will as a Government take all the measures necessary to keep our country safe, we've already announced that there will be new powers to take passports temporarily from people while investigations are taken to prevent people from travelling to places like Syria and Iraq."

Lib Dem Julian Huppert (Cambridge) questioned if Mr Hughes would look at improving the offence of treason following previous comment from the Law Commission that it was "outdated".

Mr Hughes replied: "The offence of treason has not been used since 1945, it dates from a much earlier statute.

"The Law Commission hasn't recently looked at it, there's no reason why they couldn't come forward with a proposal to do that.

"But the Government on this issue is absolutely focused on making sure people who go abroad and commit offences either abroad or when they come back to this country, which are serious offences, are prosecuted now and effectively and I hope you will accept we need to make sure we have the full panoply of powers while respecting our international obligations - and there are plenty of them without using the offence of treason."