Three people have been assessed by paramedics after the fire on Whale Island Way, which caused serious damage to the back of the property and spread to a neighbouring house.
Residents living nearby have been evacuated and taken to HMS Excellent.
Luckily there have not been serious injuries and the fire was put out earlier this afternoon – you can read the latest updates on our live blog.
The incident sparked a huge emergency response and here are a few photos which show the amazing work carried out by our police, ambulance and fire services this afternoon.
You can subscribe here for unlimited access to Portsmouth news online - as well as fewer adverts, access to our digital edition and mobile app.
. Portsmouth house fire
Police and fire crews wait at the scene of the house fire. Picture: Habibur Rahman Photo: Habibur Rahman
. Portsmouth house fire
Residents were evacuated and people were asked to avoid the area. Picture: Habibur Rahman Photo: Habibur Rahman
1. Portsmouth house fire
Residents were evacuated and people were asked to avoid the area. Picture: Habibur Rahman Photo: Habibur Rahman
2. Portsmouth house fire
South Central Ambulance Service Scas at the scene of the house explosion. Picture: Scas/Twitter Photo: Scas/Twitter
3. Portsmouth house fire
Police, ambulance paramedics and fire crews were all called out at about 12.15pm today. Picture: Habibur Rahman Photo: Habibur Rahman
4. Portsmouth house fire
A fire engine outside the house where the explosion took place. Picture: Habibur Rahman Photo: Habibur Rahman