Ghana has been ranked last among 76 countries across the world in the latest biggest ever global school rankings on mathematics and science.

Other countries in the lowest ranks are Oman, Morocco, Honduras, South Africa which were ranked 72, 73, 74 and 75 respectively.

Singapore heads the table, followed by Hong Kong, with all other African countries cited in the report at the bottom.

The Organisation for Economic Cooperation and Development (OECD) think tank says the comparisons - based on test scores in 76 countries - show the link between education and economic growth.

"This is the first time we have a truly global scale of the quality of education," said the OECD's education director, Andreas Schleicher.

"The idea is to give more countries, rich and poor, access to comparing themselves against the world's education leaders, to discover their relative strengths and weaknesses, and to see what the long-term economic gains from improved quality in schooling could be for them," he said.

The top performer, Singapore, had high levels of illiteracy into the 1960s, said Mr Schleicher, showing how much progress could be made.

The UK is in 20th place, among higher achieving European countries, with the US in 28th.

The rankings are based on an amalgamation of international assessments, including the OECD's Pisa tests, the TIMSS tests run by US-based academics and TERCE tests in Latin America, putting developed and developing countries on a single scale.

The findings will be formally presented at the World Education Forum in South Korea next week, where the United Nations is to convene a conference on targets for raising global education by 2030.

Below is the full list of countries included in the report

Countries ranked on maths and science

1. Singapore

2. Hong Kong

3. South Korea

4. Japan (joint)

4. Taiwan (joint)

6. Finland

7. Estonia

8. Switzerland

9. Netherlands

10. Canada

11. Poland

12. Vietnam

13. Germany

14. Australia

15. Ireland

16. Belgium

17. New Zealand

18. Slovenia

19. Austria

20. United Kingdom

21. Czech Republic

22. Denmark

23. France

24. Latvia

25. Norway

26. Luxembourg

27. Spain

28. Italy (joint)

28. United States (joint)

30. Portugal

31. Lithuania

32. Hungary

33. Iceland

34. Russia

35. Sweden

36. Croatia

37. Slovak Republic

38. Ukraine

39. Israel

40. Greece

41. Turkey

42. Serbia

43. Bulgaria

44. Romania

45. UAE

46. Cyprus

47. Thailand

48. Chile

49. Kazakhstan

50. Armenia

51. Iran

52. Malaysia

53. Costa Rica

54. Mexico

55. Uruguay

56. Montenegro

57. Bahrain

58. Lebanon

59. Georgia

60. Brazil

61. Jordan

62. Argentina

63. Albania

64. Tunisia

65. Macedonia

66. Saudi Arabia

67. Colombia

68. Qatar

69. Indonesia

70. Botswana

71. Peru

72. Oman

73. Morocco

74. Honduras

75. South Africa

76. Ghana