Leaving a job soon after starting

Hi all

I was dismissed from my previous long-term job earlier this year (gross misconduct, long and unpleasant story). I was in a panic and given the COVID situation I took the first job that came along – a 12-month fixed term role with the local authority. This role is paying substantially less than what I was earning (approx. 22,000 less) and I have now been there approx. 6 weeks. I am enjoying the role but at the same time it is not my dream job. I get on well with the team and the working environment is very flexible and I can work from home.

Earlier in the year I applied for a job I really wanted to do. I had an interview; the feedback was excellent but was then put on hold due to COVID. Given the time that elapsed I thought this role was dead in the water. Last week, I had the news that this company are looking to offer me the job. This is a permanent job, paying double what my current place is paying, excellent benefits and working slightly less hours in an industry that I am really interested in. Obviously, this role is far more stressful that my current one, and I have been told that expectations are extremely high and a very steep learning curve.

I am concerned that I am letting my current employer down by leaving so quickly. I have checked my contract and it allows for early termination on both sides by giving a one-month notice period. I am on a 12-month fixed term contract currently but have been told that this is likely to go permanent or be extended upon this finishing (obviously not guaranteed). Am I being unreasonable and letting my current company down by leaving so quickly? I just feel a permanent role in this climate, paying double what I am on now is too good an opportunity to pass up. I’m also slightly concerned that this is a new industry and that if I can’t meet their high expectations, I can easily find myself being unemployed (although I suppose this is a gamble with any job move or promotion).

Any advice?
Thanks