559. Extension of powers where payment is deferred with provision for earlier payment in certain circumstances.

Where by a mortgage1 of land which consists of or includes a dwelling house2, or by any agreement between the mortgagee and the mortgagor3 under such a mortgage, the mortgagor may pay the principal sum secured by instalments or otherwise defer4 payment in whole or in part, but provision is also made for earlier payment in the event of any default by the mortgagor or of a demand by the mortgagee or otherwise, then for the purposes of its powers to delay giving possession5 the court may treat as due under the mortgage on account of the principal sum