###Should I lie ... ? No.

Lying in the professional world can come back to you in unexpected way. As an example : what if the company asks you for your previous contract, as a piece of the background check ? Then they will see a lie (and probably a big one, if you're talking about a x2 factor), which might endanger your employability.

However, asking for double your current pay could be a bad signal. The employer might wonder, for instance, why you are underpaid. You should prepare a solid answer to the past salary question, which could be the following : My salary in the previous job was not in line with my expectations and the market rate, which is one of the reasons why I decided to change jobs. I am now aiming at [Salary range XXXX-YYYY per annum] for this job. If the employer really wants to know, they will just request your previous contract in the background check anyway.

Should I lie ... ?

No.

Lying in the professional world can come back to you in unexpected way. As an example : what if the company asks you for your previous contract, as a piece of the background check ? Then they will see a lie (and probably a big one, if you're talking about a x2 factor), which might endanger your employability.

However, asking for double your current pay could be a bad signal. The employer might wonder, for instance, why you are underpaid. You should prepare a solid answer to the past salary question, which could be the following : My salary in the previous job was not in line with my expectations and the market rate, which is one of the reasons why I decided to change jobs. I am now aiming at [Salary range XXXX-YYYY per annum] for this job. If the employer really wants to know, they will just request your previous contract in the background check anyway.