What do we need to do to take our friends children abroad for a trip. 
We are taking a day trip from England to Dublin in the Irish Republic
with my neice's children aged 11 and 13.  I need to be sure that they
are safe and I need to know what I have to take with us.

I'm Irish, living in England.  This is something I've done with my
younger cousins a number of times.

The answer is easy ... you do't need to do anything except to ensure
that you have purchased the tickets.

One thing that may apply, whether or not you bring the children, is
that some forms of travel require all adults to have photo i.d.
(drivers license or passport).  You do not need a passport to travel
between Ireland and England, but some companies insist on some form of
photo i.d.

Good luck,

Enjoy your trip !

You may also need to get written permission from the children's
parents before you take them out of the country toprove you're not
kidnapping them!

I agree with the last post, that most airlines require photo IDs for
security reasons. Personally I would contact your airline for advice,
as well as the Irish authorities - maybe the Irish embassy in London.

I'm British (now living in the US) and last Dec I took my daughter to
Dublin, flying out of East Midlands.  She needed her photo ID for both
the flight and to enter Ireland.

Have a great holiday!