Making a marriage legally valid.
If
someone has been married in a way that is
not recognised as valid in the United
Kingdom, the marriage can take place again
according to United Kingdom law provided
that both partners meet the requirements
described earlier. This will make any
children legitimate under the law, and will
ensure that the couple can get tax
allowances available to married couples.
There may be other advantages, for example,
some pension and insurance policies are not
payable to cohabitees, only to married
couples.