You need a special visa for foreign nationals entering the UK from Ireland. It's called a Joffi ( Johnny foreigner from Ireland) this must be applied for unless you are a Irish national, it can take several years to process as the waiting list is rather long. If you insist in applying for your Joffi write directly to HM.Queen Elizabeth stating your intentions whilst visiting our fair isle. On receipt of your Joffi (you must show the ability to raise funds of £250.000 before processing) put on your (supplied) kevlar vest and queue at the border, as this can take several days at the Joffi line, take a packed lunch. Welcome to the UK.