Can you gain admissions to a top UK Engineering PhD program with limited research? Background.
I completed both a BS and MS degree in Engineering, from a decent US University.  My Masters GPA was 3.75/4.00.  I have since left the program and began working. I want to enter a top UK Engineering PhD program but my research might be slightly subpar, depending on the standards.  During my time as a Masters Student, I was only 2nd author of 1 journal paper and 1 conference paper.  I was NOT 1st author of any publication.

Questions.    


  
  Can you get into a top UK Engineering PhD program (Imperial, Cambridge, UCL, Oxford) with limited research experience (in my case, zero 1st author publications)?
  What are the credentials of a competitive candidate for top UK universities (for an Engineering PhD)?
You are not expected to have any research publications at all to enter a UK PhD programme, even at Oxbridge. Any you have will put you in good stead. Most entrants to UK PhD programmes come from an undergraduate course or a masters programme where they have learnt lots but only undertaken research within limited parameters. Many will have only completed a project and written an unpublished report.
A first class undergraduate degree, a 2:1 is sometimes acceptable; but because undergraduate scoring is not standardized across UK (or worldwide) universities there will be an extended interview. You will need to be able to demonstrate your knowledge and your capacity to reason with a good performance during the interview(s) with your prospective supervisor and probably others in the department. The interview is also an important chance for you and your supervisor to find out if the two of you will be able to work together closely in the future.