Based on our personal experience, we have selected these safe and secure online bookmakers:
Our Top rated bookmaker! Click the link to find out the offer available for your country of residence. T&Cs apply. (Gambling responsibly 18+).
Open Account Offer(UK)
Bet £10 & Get £50 in Free Bets for new customers at bet365.
Min deposit requirement. Free Bets are paid as Bet Credits and are available for use upon settlement of bets to value of qualifying deposit. Min odds, bet and payment method exclusions apply. Returns exclude Bet Credits stake. Time limits and T&Cs apply.
Link: https://www.bet365.com
€100 welcome bonus
Get 50% up to €100 extra on your first deposit at 10Bet. Make your first real money deposit via web or mobile with bonus code FD10BET, and you'll get a 50% up to €100 bonus.
18+. New customers only.
Terms and conditions apply.
Eligibility requirements apply.
Link: https://10bet.com
Pinnacle is one of the world’s largest, fully licensed, online sportsbooks. The company has customers in over 100 countries and the website is available in 19 different languages. Pinnacle became the first sportsbook to introduce a reduced margin pricing model or reduced vigorish, thus deriving profit from lower margins but a far higher turnover. Pinnacle offer betting limits with confidence as high as $50,000 or more on selected games with their low margin pricing model.
Go to Pinnacle web site: 
100% bonus on the first deposit up to €100
How to get your bonus:
1. Register on the 1xBet website.
2. Fill in all the fields in My Account.
3. Top up your account up to €100 (or equivalent in another currency).
4. The bonus will be credited to your account automatically after the deposit is made.
Terms and Conditions apply 18+.
Link: https://1xbet.com
Bwin are one of the world's biggest bookmakers, thanks in part to their high-profile partnerships with Real Madrid, Milan and Bayern Munich.
Bwin offers up to 30,000 bets daily with betting action in more than 100 sports, the entire line-up is available in more 20 different languages. Enjoy gripping entertainment online: thrilling sports bets with a unique live feeling, get closer to the action than ever before. And then there's the casino atmosphere at its finest, live poker and numerous games for that short break in-between. Join Bwin to get away from your daily routine and enter a world full of emotions.
Bwin currently offers a £10 Backup bet T&Cs.
Website: https://www.bwin.com