“ enter upon … Lough Neagh and to use such buildings engines machinery plant or equipment of the Licencees now existing or hereafter to be constructed or installed with the consent in writing of the Owner such consent not to be unreasonably withheld as may be necessary or convenient for the purposes aforesaid. ”
“ (1) This section applies to a disposal of an asset which was held on31st March 1982 by the person making the disposal. (2) Subject to the following provisions of this section, in computing for the purpose of this Act the gain or loss accruing on the disposal it shall be assumed that the asset was on31st March 1982 sold by the person making the disposal, and immediately reacquired by him, at its market value on that date. ”
“ If and so far as, in a case where assets have been merged or divided or have changed their nature or rights or interests in or over assets have been created or extinguished, the value of an asset is derived from any other asset in the same ownership, an appropriate proportion of the sums allowable as a deduction in the computation of a gain in respect of the other asset under paragraphs (a) and (b) of section 38(1) shall, both for the purpose of the computation of a gain accruing on the disposal of the first-mentioned asset and, if the other asset remains in existence, on a disposal of that other asset, be attributed to the first-mentioned asset. ”
“ … the Crown submits, and in my judgment rightly, one has to ascertain the nature of the lease, and whether one lease is part of another or is a separate asset, by reference to the status of the lease under general law. … I cannot say that I find [section 43] altogether easy, but it seems to me that in the present case the conditions for the application of [section 43] cannot be said to have occurred. It cannot be said that the 1960 lease had been merged; nor has it been divided; nor has it changed its nature. Then, can it be said that ‘rights or interests in or over assets have been created or extinguished’? Again, I cannot see that any right or interest in or over the 1960 lease has been created or extinguished. All that has happened is that the 1960 lease has expired. ”
“ It is settled that an estoppel by convention may arise where parties to a transaction act on an assumed state of facts or law, the assumption being either shared by them both or made by one and acquiesced in by the other. The effect of an estoppel by convention is to preclude a party from denying the assumed facts or law if it would be unjust to allow him to go back on the assumption: The August Leonhardt [1985] 2 Lloyd's Rep. 28; The Vistafjord [1988] 2 Lloyd's Rep. 343; Treitel, Law of Contracts, 9th ed., at 112-113. It is not enough that each of the two parties acts on an assumption not communicated to the other. But it was rightly accepted by counsel for both parties that a concluded agreement is not a requirement for an estoppel by convention. ”