apologies to anyone who is trying to read this reply. Keyboard was causing pronblems. For anyone still with me.....
You can't assign a pension, so the lender relies on three things.
*that you will maintain your pension contributions.
*That the pension contributios will perform as expected
*That you will use a chunk of the money to pay off the loan balance at say age 60 or 65
For these reasons the pension mortgage is usually used for more commercially oriented property transactions. E.g. buy to let or more often for professionals or the directors of small limited companies to aquire properties to rent to their own businesses. In such circumsatnces good tax-breaks are generated.
In a personal pension plan, (or as a proprietory director) you can take 25% of the fund as a tax-free lump sum, and use this to clear the mortgage, so therefore, in theory, you need to have a pension fund of 4 x loan amount. However lenders may want a safety margin and look for a target fund of say 5x loan amount.
If you go the ARF route you can have more cash. e.g. fund 1,000,000.
(a) Tax-free cash 250,000, (b) directed to AMRF 63,500. (c)This leaves a further 686,500 that can be drawn down but which suffers tax @ 41% and levies at 2% yielding another €391,305 or a total of 641,000 in cash.
In some cases taking all of the tax breaks into account, and the love of bricks an mortar, borrowers will make decisions to go this route and have a rentable property at the end rather than a traditional pension.
In other cases the intention all along will have been to sell the property and pocket the capital gains, with rent having covered the interest only payments in the interim. In such circumstances the pension fund remains intact, and was simply a "comfort" to the lender and the borrower and a tax-effiecient comfort at that.
All in all, many advisers will recommend the pension backed mortgage for small (and not-so-small ) business oweners and self-employed. Many advisers would shy away from trying to arrange it on a family home.
For further coverage you can readup in "Tax-magic" by Alan Moore
(are we allowed to recommend relevant books on this forum ?)