Donald Trump: How you can get banned from coming to the UK and why

At last count, 300,000 people have signed a petition calling for US presidential hopeful, Donald Trump, to be banned from entering Britain.

He says he supports temporarily stopping Muslims from coming to the US - something which has caused outrage around the world.

His comments may be offensive but could they get him banned? In theory, yes.

You're essentially "banned" from the UK if the government refuses to give you a visa.

Terror suspects and criminals are the people we hear most about being stopped. But Donald Trump wouldn't be the first celeb to be stopped.

Chris Brown was banned in 2010 for being guilty of a serious criminal offence, according to the Home Office

After leaking US state secrets Edward Snowden was not allowed into the UK

America's answer to chef Delia Smith, Martha Stewart was jailed for "obstructing justice" and later refused a UK visa

Tyler the Creator claims his lyrics got him banned earlier this year

Boxer Mike Tyson was banned because of his rape conviction

Shirley Phelps, part of the Westboro Baptist Church which pickets military funerals and condemns homosexuality, was found to "foster hatred"

The UK Border Agency is run by the Home Office. They set the rules for who can and cannot get a UK visa.

From the hundreds of pages of guidelines available online you can see there are some general reasons to be refused.

If a person's been convicted and jailed for an offence they can be stopped.

However, it depends on how long the jail sentence was and when it was served.

Other general reasons can include if a person has submitted forged documents, if your home government has issued you with a travel ban (EU & US citizens), if you've broken immigration rules before or if you have a disease that could be a risk to the general public.

There are also some famous examples of individuals who've been banned from coming to the UK because they are considered a "threat to national security".

But the petition hopes to get Donald Trump stopped for "hate speech".

This could potentially happen under the two final categories for refusal: Exclusion Conducive to Public Good and Secretary of State Exclusion.

Exclusion Conducive to the Public Good

The UK Border Agency can turn someone away if they feel their "character, conduct or associations" would not be "conducive to the public good".

That could include, for example, being a member of a banned group or being a person who might encourage others to break the law.

The key bit for Donald Trump, critics say, is "a person whose presence is undesirable because of their character, conduct or associations".

Secretary of State Exclusion

If all else fails the Home Secretary can personally ban someone if he/she feels it's for the public good.

Theresa May said radical preacher Abu Qatada "would not be coming back to the UK" in 2014

The current Home Secretary, Theresa May, has said she will not comment on individual cases but a statement from her department says: "The Home Secretary has the power to exclude any individual if she considers that his or her presence in the UK is not conducive to the public good.

"Or if their exclusion is justified on public policy grounds."

"Public policy grounds" would mean if someone tends to support breaking the law or they risk harming "the state or its citizens".

It's a judgement call and last year Mrs May said she had excluded "hundreds" of people.

Once a petition has more than 100,000 signatures it will be considered for debate in parliament.

However, that's not guaranteed to Mr Trump, not least because it could be politically uncomfortable if he does go on to be voted in as the next US President.

He's among 14 candidates hoping to win the Republican Party's nomination.

It's reported Downing Street has indicated that as Donald Trump has no plans to visit the UK, the debate is "hypothetical".

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