Switching to TIER 2 VISA from a work permit dependent VISA

I am on a work permit dependent VISA and based in Jersey Channel Islands and my VISA expires in 2015 June. I now got a job in UK, and would like to apply for a TIER 2 General VISA.

My questions are
1. Do I have to leave the UK to switch the VISA, I have some friends who were on work permit VISA in Jersey/Guernsey and they switched inside the UK (please nite that they were not dependants),
2. If I leave the UK, do I then forfeit the time I have stayed in Jersey so far, when I apply for naturalisation.

Thank you for your assistance

Apply outside the UK. Time in the UK until now is only relevant if you apply to settle as a dependant or under long residence. It will not be relevant to ILR in a work category.

Hi,

At present I am on Tier 2 ICT dependent visa(work permit), dependent on my spouse. My spouse visa expires in June 2014 (we were in UK from May 2013 - 1 year short term ICT ) so default mine too.
Since visa is short term ICT it cannot be extended.

I am already in contract job and want to continue in UK for few more years.
Questions :

1) Is it possible for me to switch to Tier 2 General visa in May 2014 by staying in UK itself ? (I spoke to some of the sponsors they said, may be possible).