Time required to get through Heathrow Airport

No one knows this answer.

Too many factors involved like how many other flights are arriving at the same time, where you are sitting in the plane, how many immigration agents are working,etc.

I’ve done it 25 minutes and in 2 hours....it’s always a crap shoot.

Heathrow is huge and the walk alone to immigration can take 10-20 minutes depending on the gate.

Give yourself 3 hours at minimum especially with an infant.

Hi boys,

So you have a flight to Heathrow, but you have not booked a connecting flight to wherever you are going?

I always allow at least a 2 and 1/2 to 3 hour layover. But, that is with a pre-booked ticket with connection.

Gate assignments can change at the last minute. One time at Heathrow I was assigned one gate to go to Rome's airport, but at the last minute the gate number changed and was assigned a few gates down.

you may be slowed down carrying an infant and whatever carry-on luggage you may have too. Maybe Heathrow has some special carts for you to wheel your infant and your luggage.

maybe someone who is more familiar with the airport can help.

Really need the terminal(s) the two flights operate from at the least to give sensible advice. Heathrow is effectively 3 or 4 separate facilities depending on how you categorise them and the time between each and even within each varies so much.

I frequently fly into London with the intention to fly somewhere else in Europe on a different ticket and I always schedule at least one overnight in London. Not only does it sometimes take hours to get through border patrol (and I don't even check luggage or have an infant) but if the first flight is late and you miss the second one they have no obligation to get you to your destination. You are now stuck with no hotel, no flight (they can be sold out for days at the last minute). Just too risky. I have easily taken more than two hours to get off the plane, to and through passport control - and now you will need to get to the next terminal (unless it's in the same terminal, but even that will only save you a little time), go through security and check in again (at least two hours before that flight). If you do want to do this I would allow five hours. Heathrow is huge, five separate terminals and British passport control takes longer than any other European country I've flown into.

The one thing going for you in terms of passport control is that you're very likely to be directed to the 'family line', i.e. the line for those with children which is typically shorter than the 'normal' line.

Depending on when you arrive, you may be able to use the E-gates if travelling after June. This could take a few minutes or much longer depending on the line.

Does booking the trip as two separate flights really save a significant amount of money to make the risks of missing the 2nd flight really worth it?

Driving 10 miles out of your way to save 2 cents a gallon on gas may not really be a "saving"

Depending on when you arrive, you may be able to use the E-gates if travelling after June. This could take a few minutes or much longer depending on the line.

The E-gates can only be used by people aged 12 and over so the infant will not be able to use them.

Since you will be on separate itineraries given you haven't purchased your 2nd flight, allow a minimum of 4 hours.