"6. We hold that the contract of employment was tainted with illegality. Mrs Hall was turning a blind eye to the fact that the Respondents were not paying tax on part of her income. Where the payslips differed from the money she received each week there is only one logical conclusion, namely that there was an intention by the Respondents not to pay all the tax that was due. Indeed Mrs Hall was told by the Respondents that was the way they did business and she in our view knew that the Inland Revenue were being defrauded."