I think it is a minimum of 10 or 7 years of N.I. payments paid in her name, to get a % of the 35 year full pension at whatever the retirement age is at the time she wants to retire, think it is 65 at the moment for women....
UK pensions are now paid on an individuals' status....
Few years back I tried to sort out a Thai widow's UK state pension because she had a N.I. number, but back then the husband who claimed on his pension for a Thai wife, got a N.I. number for her, she thought she was going to get a pension, I spoke to pensions on her behalf after hubby departed, she got nothing....