My new house was obviously previously home to a heavy smoker. The ceilings, walls and woodwork are very badly stained and coated in the vile yellowy substance. The house also stinks of stale smoke (flooring was already stripped out).
What's the best way to clean it off walls and will I need to use any kind of primer or undercoat on walls before painting to fully stop smell and staining coming through new paint? If so what's best?