If you have applied for a National Insurance number and are in the waiting period (10 days – 4 weeks) you can still work. As long as you have applied for your National Insurance Number this will not impact your ability to begin work. You must provide your documents that state you have the right to work in the UK and inform your employer that you have applied for a national insurance number. Once it has arrived, make sure that you provide this to your employer so that you can be taxed correctly.