National Insurance Contribution
If you work for more than one employer you will normally have to pay Class 1 National Insurance contributions in each job in which your earnings exceed a prescribed minimum level, known as the Primary Threshold.

Your employer will pay secondary contributions on all your earnings above a prescribed threshold, known as the Secondary Threshold but you will pay primary contributions only on earnings in excess of the Primary Threshold, up to and including a prescribed Upper Earnings Limit.

Full details of current earnings limits and National Insurance contribution rates are in leaflet GL23 Social Security benefit rates which is available from the post office. If you earn less than the appropriate prescribed threshold neither you nor your employer will pay contributions.

If you work for an employer and are also self-employed you will normally have to pay Class 1, Class 2 and perhaps Class 4 National Insurance contributions.

Types of moonlighting jobs
Often moonlighters are restricted to working in the evening or early morning to fit their second job around their first. This can limit the type of work available. That said, there are alternatives to working behind a bar:

Skilled Moonlighting
People with desirable skills such as computer programming, typing and foreign languages can put these to use outside of their everyday job, moonlighting as a freelance.

The skilled moonlighter is often able to work from home and wages are generally more attractive.

Moonlighting Tips