From the Telegraph and Times of 8 April 2016: BUTLER - On 11th October 2015 to Viscount and Viscountess Mountgarret, a son, Theo Oliver Stafford.
The 18th Viscount MOUNTGARRET (b 1961). He m 1st 1995 (div 2000) Laura Brown GARY d of Mrs Albert Dickens Williams Jr of Lake Forest, Illinois, USA, and had 2 daus.. He m 2nd 2006 Fenella M (b 1965 reg Q2 Cheshire) d of David S FAWCUS and (m 1961 reg Q4 Cheshire) __ WOOD. Their dau, Hon Venetia Ellice Cara was b 2013.
Lord Mountgarret now has an heir apparent to the title. The only other known person in the line of succession is Lord Mountgarret's brother Hon Edmund Henry Richard BUTLER (b 1962), who was briefly married in the late '80s and is now unm with no issue.