Nature of a beneficiary’s interest under a discretionary and irrevocable trust

I am discussing with a consultant, who states that in a trust deed (discretionary and irrevocable trust) can be included the class of beneficiaries identifying it as follows:-
“a) Primary beneficiaries as descendants which will include anyone born down their bloodline and
b) Secondary beneficiary a named/specified charity in case the primary beneficiaries are not alive”.

The nature of the interest of a discretionary beneficiary of a discretionary trust, is that they don’t usually have a present right to enjoy property, nor do they have an immediate entitlement to the income/capital, as well as no contingent interest in a trust property.
The difficulty on my side, is to accept the wording regarding the “secondary beneficiary”.

I am inclined to think that a secondary beneficiary in such a case, does have a ‘contingent interest’ and not (as it should) an expectancy or mere possibility of a distribution in their favour.

Thank you very much for your attention.
Regards
Sarah

The wording for the secondary beneficiary looks to me like a form of a Default Clause.

Is there a more conventional default clause?

Thank you very much Karl.

I also had this hypothesis in mind, but the draft already has a default clause:

“6. ULTIMATE TRUSTS

Subject to Clauses 3 to 6 inclusive, and if and so far as not wholly disposed of for any reason whatever by the provisions of those clauses, the capital and income of the Trust Fund shall be held upon trust for such charities or charitable purposes as the Trustees shall select.”

Thank you very much for your help.
Kind regards
Sarah