Facts:

In 2009, the 1st appellant entered into a contract with the 3rd respondent. The 2nd appellant is a company based in Portugal while the 3rd appellant is based in France. There were some aspects of the contract assigned to the 2nd and 3rd appellant which involved surveys and deliveries to be done offshore and outside of Nigeria. The 1st respondent is an agency of the Federal Government responsible for the management, administration and collection of taxes accruable to the Federal Government. In 2011, the appellants wrote to the 1st respondent to inquire whether the contract between them and the 3rd respondent was subject to Companies Income Tax, Withholding Tax and Value Added Tax. The 1st respondent replied the letter to the effect that since the foreign companies involved in the contract are domiciled in countries which have double taxation agreements with Nigeria, the activities of the companies are not subject to taxation provided that such activities are not carried out in Nigeria. The 1st respondent also stated that its advice is subject to the provisions of the Companies Income Tax Act and that the other parties to the contract such as the 1st appellant is not so exempted.
The 1st respondent consequently reviewed its position on the matter and the activities of the appellant and decided that they were subject to payment of Companies Income Tax, Withholding Tax and Value Added Tax. It therefore sent demand letters to the appellants requesting payment of tax on the contract and the activities of the appellants in Nigeria. The appellants denied liability and relied on the earlier correspondence with the 1st respondent as the basis for their exemption from payment of taxes to the 1st respondent. The appellants took it a step further by filing a suit against the respondents at the Federal High Court, Lagos Division seeking the determination of questions bordering on whether they were liable to pay Companies Income Tax, Withholding Tax and Value Added Tax and whether their activities offshore were liable to be taxed. They also sought the determination of questions concerning the issue of double taxation agreement between Nigeria and the countries where there are based; whether they are liable to pay taxes in Nigeria and in their countries of origin.
Furthermore, they sought to know whether the 1st respondent is not estopped from resiling from its earlier stance that they were not liable to pay Companies Income Tax, Withholding Tax and Value Added Tax. After hearing the parties, the trial court ruled against the appellants and held that they are liable to pay income tax to the 1st respondent, but not Value Added Tax which the court stated to be a consumption tax not related to the activities of the appellants and that it was the 3rd respondent who has the obligation to collect and remit Value Added Tax accruable from the contract to the 1st respondent. The appellants were dissatisfied with the decision of the trial court and filed a notice of appeal at the Court of Appeal, Lagos Division urging it to reverse the trial court. The 1st respondent also filed a cross appeal challenging the part of the judgment of the trial court exempting the appellants from paying Value Added Tax. One of the issues for determination is whether the 2nd and 3rd appellants are liable to pay Companies Income Tax and Withholding Tax pursuant to the Companies Income Tax Act.