However, by the time the charity’s animal collection officer Jill Sanders had arrived at her flat in Kensington, west London, the snake had slithered away and could not be found.
Ms Sanders said: “The poor resident must have had the fright of their life waking up to a snake in their bed.
“They jumped out of bed and closed their bedroom door to contain the snake but, when I arrived, I couldn’t find where the python had slithered to.
“I left my details and told them to contact me as soon as they saw it again.”
The python was eventually caught by Ms Sanders in a corridor the following evening when she was called back to the flat.
The RSPCA does not know how it got inside the property, but believes it must have escaped from its owner nearby.
The animal welfare charity says it collects more snakes in the summer as they have more energy in the warm weather and are good escape artists.
Ms Sanders added: “I’ve been called out to a number of stray snakes in recent weeks and many of these appear to be escaped pets.