Filing a UK tax return

I'm working & living in the UK, but still doing some part time remote contracting work for my previous employer in the US. Would this be taxable income for the UK, and force me to file a UK tax return (as stated here - http://www.hmrc.gov.uk/sa/need-tax-return.htm)?

Am I correct in reading that if not for this potential issue, I wouldn't have to file a UK tax return?

Thanks!

What is your UK visa and residence status? How long have you been in the UK?

Tier 2 General visa, and I've been here since January 6th of this year.

Is this an inter company transfer and what are your intentions? do you intend to stay in the UK for a year, 3 years or longer, what is the purpose of your stay? This is why I ask.

http://www.hmrc.gov.uk/cnr/hmrc6.pdf

This job is with a new company in the UK. We're planning to stay about 3 years (leaving before we have to renew our visas).

It sounds as if you are resident and because of recent case law you might also be ordinarily resident

http://www.mcguirewoods.com/news-resources/publications/international/53110EuroWatch.pdf

This is an area of great confusion and professional advice or a coll to HMRC might be warranted

When would I have to file UK taxes if I just moved here?

Info you need is here.

http://www.direct.gov.uk/en/MoneyTaxAndBenefits/Taxes/SelfAssessmentYourTaxReturn/index.htm