Iains is perfectly correct. An asylum seeker has to be processed in case they are not being truthful and are here for other purposes.
An unknown arrival to our shores may have a serious criminal record, and/or be a risk to us in many ways.

About ten years ago I was asked by a church organisation to befriend a young Cameroonian lad who had arrived here from Sweden (of all places!) where he had been accepted as a student. He requested asylum saying that he had been politically active against the Cameroonian regime, and had been threatened with death. (He hadn't asked Sweden to accept him!)

The church concerned housed him for free with a Christian family, and he was fed and clothed. (An asylum seeker is not allowed to seek work, but receives a tiny amount on which to live.)

Eventually, his application was processed, and the Home Office found he was not in any danger, had lied about several things and was merely seeking UK residency. He had been in trouble with the Police in Cameroon and was definitely not a suitable person to have living here.

When he told me all about his asylum failure, he grinned, winked and said at least he'd had a try! I wasn't particularly amused.
He was deported shortly afterwards.
He was not a fluffy bunny, that's for sure.

My husband's character and history was examined by the Home Office, including references from his Embassy and his employer at the Port of Abidjan, where he'd found work as a security guard. I think this was right. He could have been a Muslim terrorist, a thief, even a murderer...