You could be economical with the truth without lying, as such. Say the reason you & your employer parted ways was that due to "restructuring of existing staff levels" they had no other option than to let you go, and mumble something about the fact that despite you progressing in leaps and bounds in terms of responsibility, the fact is that you weren't the longest serving member of the team, so when cuts were made....(and trail off wistfully at this point)
Technically, the part about restructuring is correct, because if they sacked you they restructured their staffing level to accomodating getting rid of one
person, i.e you, so you're not lying! Say you were "let go", never
let slip the word "sacked" or "terminated" when being interviewed (sounds daft, but it's easy when an interviewer asks if you've been sacked to say, "erm...well...) And bull**** this point - say something NICE about the bastards who sacked you, such as how they really helped and supported you at every turn. That way, if the interviewer contacts your previous employer and the employer says anything less than favourable about you when asked for a reference, the ex-employer will come off as looking vindictive and nasty while YOU while come across to the interviewer as utterly gracious and able to see the best in everybody, which may very well mean getting that job!
Unless you were sacked for something like theft or drunkeness on the job or something as blatant as that, most employers, if they sack someone, will give a "basic" reference, which just confirms they employed you between such and such time.
Have you worked anyplace that you left on good terms? If so, contact them ASAP and ask if they'd be kind enough to post you a written reference as you are attending interviews and feel this would support your application. I've obtained written references years ago from ex-employers, scanned them and saved them on disk - I found this helped to "camoflauge" the odd job or two where the company, ahem, was "restructured"
Best of luck!