Where I can verify my uk visa/working permit.my employer's agency is uk border agency.he asked me to pay basic travel allowance.

Ok, there is no travel allowance. If they are asking you to pay it, they are a fraud, they are cheating you out of your money.

Yes it's a fraud.. one guy ask me to work for him and be a nanny to his 2kids... that the salary is 650pounds per week... that they will do the visa there... and will cost 1,000pounds but I need to share some of the expenses... I told him I don't have money. He said that he just want to be sure I'm coming after the visa will be issued. Then bid to 100usd... what the hell, I mean... he want me to send 100usd to prove I'll come but his not afraid of losing 800something pounds... he think I'm idiot, play with him... make him believe you bite his bait... hahaha...