In order for you to have a job in England you need to have some kind of visa (student, spousal) or a work permit. You can't apply for a work permit, a company has to find you, want you, and get it for you. So you can't work if you go to live in England as boyfriend/girlfriend.
You can get into England to live as boyfriend/girlfriend without a visa or anything, but it's really, REALLY iffy, I I would strongly suggest not doing it. That's what I did, and I nearly got kicked out, and it was horrible. THey didn't believe my story - it looked like I was going to England to move there, not to visit. And that's not cool with Immigration. Peedal went over with her kids and got turned away and sent back to the states, and gad to have a whole different plan of attack. It's a really, really risky way of doing things.
I don't know what your situation is, so it's hard to offer any advice or suggestions... but basically in order to move to England you have to have a Student Visa, Work Permit, Spousal Visa, Fiancee Visa, Ancenstry Visa, some other kind of Visa... and I think that's all. They don't like people just coming over to live unless they know they will be supported and won't take up public funds... and that's where the Visa's come in play.
It's a sticky and horrible thing to be in love with someone overseas sometimes, cause there's the whole "we need to live together, but can't unless we get married".... and a lot of us can relate to that.

- Again, I'm not sure what your situation is so I hope I've been at least a little helpful...