US Taxes on a UK-based company?

A question:  A UK-based consulting group registered in the UK, with no US operations, does consulting work for a US company for a certain fee.  Virtually all of the work is performed in the UK, then results provided to the US company in the form of a written report.  The US company asks them for an EIN, which they obtain from the IRS and provide to their US client. 

Is the UK company liable for US income tax in this situation?

Does the US company have to withhold part of the payment as prepayment of this potential US tax?

Thanks to anyone who can enlighten me on this.

Is the "UK-based company" a CFC? (CFC = Controlled Foreign Company).  Does it have 10% or greater US owners by vote or value?

No to both.

Thanks

If your company is receiving income from U.S. source, this income is subject to U.S. tax. Obtaining TIN and providing it to your U.S. client will only benefit you; if you refuse to provide TIN, your US client is required to withhold  28% tax at source from your fees.

If they have your TIN, they will send you form 1099MISC indicating fees paid for your consulting work and also report this amount to IRS. In this case, they do not have to withhold taxes at source.

Your company will file form 1120-F with IRS and report your income from U.S. source. Existing tax treaties between U.S. and UK will allow you to use the reduced rate of taxation. Form 1120-F should be filed even if you do not owe any taxes - in this case it will be marked as "Protective return".

Thanks very much!!!