I did read the link and that applies to the USA only. In the UK, abstinence is bound by universal Canon Law as explained in the Q&A and must be observed in the majority of days or you risk mortal sin.
No, you are mistaken as regards the UK, Elizium23.
Please read the following from the website of the Catholic Bishops of England and Wales.
Q11. Are the Bishops placing a greater obligation on Catholics in England and Wales? Apart
from the exceptions above, will it be a ‘sin’ to eat meat on a Friday after the Bishops’ decision
takes effect in September?
The obligation on Catholics in England and Wales to do penance on a Friday will be the same after Friday
16 September 2011 as it was before that date. The only change is that the Bishops have determined that the
requirement by all the faithful to do penance on a Friday will be fulfilled by abstaining from meat. When asked
a similar question to this, the Holy See replied that the ‘gravity’ of the obligation applies to our intention to
observe penance as a regular and necessary part of our spiritual lives as a wholexiv.
Therefore, the ‘gravity’ of the obligation does not relate to observing the specific act of penance (abstaining
from meat) prescribed by the Conference of Bishops. The ‘gravity’ of the obligation applies to the intention to
do penance during the prescribed penitential days and seasons of the Church’s yearxv. Failure to abstain from
meat on a particular Friday then would not constitute a sin.
You note it says that failure does not constitute a sin?
(Note: I am referring to England and Wales as those countries are by far the biggest part of the UK… I should not have used the blanket term ‘UK’ as it may be different in Scotland.)