Working in the UK, paid in the US (UK non-resident)

Does anyone know the UK tax requirements are for someone working in the UK for a US employer and being paid in the US?  The number of days working the UK will not be enough for me to be considered a resident for UK tax purposes.

The information I get from HMRC seems contradictory.  The person I spoke to at the non-resident's tax centre said I am not liable for UK taxes unless I establish residency in the UK, but the forms and instructions on hmrc.gov.uk seem to imply otherwise - that any income earned this way is taxable.

Do you live in the UK?
Are you paying US taxes?

There are a lot of variables but here is a great link that helped me...
http://www.ssa.gov/international/Agreement_Pamphlets/uk.html

Live in the US, paying US taxes (US citizen so I have to pay US taxes anyway).
Non-resident UK taxpayer (have rental property in the UK).
Will need to be in the UK for work, but not for enough daya a year to be considered a UK resident.

Am getting contradictory information from HMRC about whether I will need to pay UK tax on the income that can be considered earned in the UK.

Because of tax treaties, tax credits/relief, I think this won't affect my bottom line, but I would like to know whether I need to pay tax to the UK and then claim it as a credit on my US return.

I followed the link and this is how I learned all I needed as well.

Do you have permission to work in the UK?
If you are here  on visitor visa you cannot even work for a US company since you are techinally working in the UK.

Your work status   
Coverage and taxes

You are working in the U.K.:

For a U.S. employer who:

    * Sent you to work in the U.K. for five years or less

   pay taxes to : U.S.

    * Sent you to work in the U.K. for more than five years

pay taxes to : U.K.

That site is great but it is good you are crossing all your P's and Q's

I will obtain permission to work in the UK (probably Tier 1).

The link is very helpful, but I think it refers to Social Security Taxes (US) and National Insurance (UK). I was thinking about just plain income tax.