I'd advise getting the Visa to avoid any hassle with Immigration Officers. My husband (Indonesian) who holds a Stamp 4 Irish Permit traveled through Heathrow recently (2hr stopover on way back to Ireland) and got a bit of hassle from the Immigration officer. We'd read the UK Immigration website which said that it was not necessary for citizens of Indonesia.
http://www.ind.homeoffice.gov.uk/travel ... transituk/
If you are a visa national and you are travelling to the United Kingdom simply to travel on to another country, you may be able enter without a visa (known as the transit without visa concession) if the immigration officer is happy that you meet all the following requirements:
* you are travelling to a country outside the United Kingdom, the Channel Islands, the Isle of Man and the Republic of Ireland (this is known as the common travel area);
* you arrive and leave by air within 24 hours; and
* you can continue to another country where you will be guaranteed entry.
Apparently the only exceptions to the above rule are citizens of the countries
listed here (includes India). Indonesia is not on that list which
shouldvmean that he does not need a DATV, but they insisted he did. This completely contradicts the info on the IND Website, but it's not nice trying to argue with Officials telling them they don't know their own rules.
He'd transited through LHR two times before without hassle, but this time was warned that next time he would be refused entry.
